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2011 BF15D barking and backfiring at 3/4 to full throttle...i'm stumped.

Morecowbell

New member
Just got the boat from a deceased old friend. Maybe 50 hours on this Honda and fresh water only. Replaced the fuel, (91 octane and added some seafoam), fuel filter, oil filter, plugs and fresh oil. Fires right up, let it warm up and take it to about 3/4 throttle and beyond and all hell breaks loose. Pulled carb and really cleaned it well and it had some light film but overall damn clean. Same issue though. Thought maybe it was a rev-limiter because that's really what it sounds like so I put it in forward (instead of neutral) thinking neutral might limit RPM's differently.... don't know why but regardless, same issue. Timing?? Valve adjustment?

2nd question, I need to get a service manual. Any recommendations?

Dave
 
First off, you asked yourself the same two questions that came to me too. Timing and valve lash (clearance) adjustment. Although, with only 50 hours on her, you may find all is well there.
But, years take thier toll on timing belts and I have seen fasteners like rocker arm lock nuts work loose right from the factory. So checking is a good thing.......to borrow a Martha Stewart phrase.

Make sure you're running the right NGK plug as they just seem to work better than the Denso's.

Try squeezing the primer bulb as you're revving it. If that seems to improve things, it's possible that years have also done a number on the fuel pump. I consider it not likely but it's obvious this outboard has sat a lot, so, anything is possible.

The carbs on these can be "boogers" to get properly cleaned and the little "jet set" tubes are prone to cracking. When I worked on these regularly, I finally just got in the habit of replacing them to save time and hassle.

If the accelerator pump nozzle won't throw a MINIMUM 6 foot stream of carb spray out past the open throttle plate, it's NOT clean enough.

There is a black, rubber, "FUEL CHAMBER" mounted to the engine oil dipstick. That needs to be taken completely off and all liquid shaken out of it every so often. When the fuel chamber gets an accumulation of too much water in it (it WILL at some point) it usually causes starting issues. But, clear it out anyway to see if that helps.

The ONLY shop manuals worth buying are the official Honda Shop manuals by Honda Motor Co. Ltd. Service Publication Office. The knock offs by Clymer, Sea-Loc and such are next to useless and replete with errors that could end up costing you big $$$ in the long run. Although,they are MUCH cheaper. My Honda BF15D●BF20D manual (the one for your outboard) cost $115 a couple of years ago on Amazon.

One H.E.-double-hockey-sticks-of-a-deal though is the HONDA MARINE CARBURETION MANUAL. I believe that it's still under $40 and it is a VERY GOOD BUY for anyone wanting to service the finicky Honda carbs. Very specific, targeted information about all the Honda Carb line-up that makes anyone that can read a pretty good Honda carb tech right off the bat.

But, if you're "currency challenged" (as I am at TAX TIME) there are plenty of good people here more than willing to try and help you. Just ask.

Good luck and keep us posted.
 
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Wow.... thank you so much for that information. Raining and cold today on the central Coast of California so tomorrow I will head on out and try the bulb squeeze first and pull the fuel chamber regardless and just check it out. Going to order the factory manual but I have to laugh some.... they have a specific one for the carb as well? Man, seems like they should have it all in one manual but if these carbs are like the old SU carbs on my old english cars then perhaps I should pickup that one as well. I will post my progress and again, my thanks.

Dave
 
Yeah, just like everything in the world these days, they stick you for all they can.
Those manuals are the best even though, they both could be much better than they are....in my opinion. But, if you do you're a pro, do your own work or are remote and need to depend on your efforts alone, they end up being the essential tools of keeping that outboard tip top. Not perfection but as close as you can get at this time.

I forgot to mention that the carb manual has really great, color illustrated tutorials on all the internal circuits and how they flow. As an example....did you focus on the main air jet passage when you cleaned yours?

If you're not sure what I'm talking about, it's inlet is in the main body just above the throat of the carb on the flange of the muffler mounting surface. Most people miss that if they aren't experienced with these carbs. The manual walks you through all of those "nuances" to get these things taken care of the FIRST time.

The really good news is that you have inherited one of the BEST small twin outboards ever made! They are rental fleet rugged and tried and true for the owners that do the required maintenance. Which isn't a great deal actually. Change out the water pump every 2 years in salt and 3 in fresh water, along with thermostat, keep the carb dry when put up, change gear oil every season, and change engine oil with filter regularly. That's about it except for a couple of grease zerks and cleaning coolant passageways....spark plugs every so often.....and that is about IT! HONDA, for the most part, makes GOOD STUFF!
And these BFD twins are really the BEST of thier best when reliability and ease of ownership counts.
 
Well today I cleaned the black fuel chamber. Also took the fuel pump off just to check it out. It performs well into a cup. Tried the "squeeze the bulb as it's barking and sputtering at 3/4 to full throttle" and no change. Popped the head cover off and checked the valves...perfect. Pulled the @(&*(@ carb off again, and more carb cleaner but I didn't really understand the 6' test so I need to do some more research on that.

To me I'm thinking it's leaning out. I see a NOS carb on eBay for @ $150.00 I'm tempted as this thing has my head spinning. Need to read about the ignition timing but it starts and runs so nice to the 3/4 mark. I want to put some new springs in the distributor dang it!!! I keep thinking where's the &$#*(&# adjustments on this carb???? That was a joke folks.

Tried to attach a 15 second movie but it failed. Probally to large or unacceptable file type.

dave
 
Update and more confusion. I pulled the ECU out and printed the pin outs and ohm ranges. good god... I'm way out of spec on 80% of the ranges. How can that be and still run?? I'm using a Fluke 115 True RMS Multimeter on k(ohm). So check out the data on the jpeg I have attached. What the heck?? Anyone ever see this before?

horizontal 1 - 16: 1 problems, 2,3 no specs, 4 - they were all overload on my meter (OL), 5 - two OL, 6,7 problems, 8 - NOTHING, 9,10,11,12 problems. 13 and 14 =nothing...no data, 15 and 16 OK
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Two things to try, make sure your neutral switch works and has not been by passed and try running it with the temp sensor disconnected, it could be faulty and telling CDI unit it is over heating.Don't dwell too much on the ohms test you are doing, if it runs okay at lower rpm then your ignition system in fine.
 
I agree about not worrying too much about the ohm testing. But, FYI, OL on the Fluke meter simply means "Over Limit" and, in Ohms testing, means no current flow. Which is essentially an open circuit. It's the same thing as "infinity" (an eight on it's side) on the old analog meters. It's all a way of indicating infinite resistance.

I've seen many guys, including myself, not be able to make much sense out of those Honda pinout charts so what iang6766 says makes perfect sense to me.
 
Hi Dave,
Question: when you cleaned the carb, did you remove the jet set tube? (item 18 inside the nozzle, #20) in the parts page link below.

If you did, did you use a new oring? (Item 1, part of the gasket set)

This is really critical to the operation of the carb. It's easy to "miss a spot" on that tiny tube and they are also prone to cracking. It is also very easy to damage the oring when reinstalling the tube. Use a bit of lube, WD-40 works, to help it pop into it's groove and not pinch.


https://www.boats.net/catalog/honda...p/bf15dk3-lrta-2007-and-later/carburetor-auto

The above link is for reference to what I'm writing. It depicts an auto start carb. You may have a manual choke but, otherwise they are very similar.
 
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Hi again Dave,

I want to clarify the 6 foot stream of spray from the accelerator pump nozzle.

https://www.boats.net/catalog/honda.../bf15dk3-lha-2007-and-later/carburetor-manual

Number 14 in the MANUAL CHOKE carb parts link above is the accelerator pump. It shoots a burst of fuel out of a tiny nozzle drilled into a small brass tube that juts out into the carb throat at the entrance to the Venturi.

When cleaning one of these it's important that you locate the passageway that feeds that tube and make sure it is clean. You must remove the float chamber and then determine the passage in it that the accelerator pump piston pushes fuel through to the main body when the piston is stroked downwards. The passage in the float chamber will, of course, match up with the nozzle feed passage when the chamber is mated to the main body. Spraying cleaner into that passage should have fluid coming out of the nozzle. If not, the nozzle is likely totally plugged.

Find a way to prop open the throttle plate fully. I use a small, pocket screwdriver jammed in the linkage after I've opened the throttle fully. With the throttle plate propped open, you can look through the Venturi from the rear of the carb and see the accelerator pump nozzle and tube.
Use the plastic straw on your can of cleaner and carefully place it directly over the nozzle orifice and give it a shot of cleaner. Fluid should flow out of the passageway I told you to locate earlier. If no flow occurs, don't worry, I haven't seen one yet that won't clear if you keep after it.

Try spraying fluid into the passage to get fluid to exit the nozzle. This is where you will eventually want to see the 6' stream coming out past the throttle plate at the rear of the carb.
BE CAREFUL AND WEAR EYE PROTECTION while doing this!

If the stream is weak or non existant, repeat by placing the straw over the nozzle and "back flushing" the tube and then go back to the tube feed inlet and spray there again.

Keep doing this until you get get the long stream I describe. It can take many tries and a can of fluid or more to clear a badly clogged tube.

Also, while you have the throttle plate propped completely open, you will be able to see and access ALL of the fuel feed orifices at the top of the carb throat. Use the spray straw to cover each orifice and back flush each, one at a time. This is best done with the jet set tube and idle mixture screw removed. You will see fluid coming out of the idle mix cavity when you hit the idle orifice and you'll see fluid flow from the main passage where the jet set mounts when you spray the transition and full speed orifices respectively.

As a matter of fact, your full speed orifice may be plugged judging by the symptom you describe so this is a good thing to try before loading the parts shotgun.

After back flushing the orifices, you can foreflush the passages by inserting the straw where you saw fluid exiting when spraying the orifices. The fluid comes out of several places at once when doing all this and I've learned to use my fingers and thumb to block the fluid from as many "exits" as possible to increase the spray cleaning power when working on a particular circuit.

I hope this helps you but I won't blame you if you're a bit confused.

Keep us posted.
 
So I tested the nuetral switch and it's fine. Pulled both connectors and had tone when I touched them with the MMeter leads. Tone stopped once I put in in FWD or REV. Pulled the wiring cap off the overheat switch and fired it up with the same old results. So I just printed out your latest post and will head out to the shop and pull the #*&$#(- carb again and follow your instructions. It's getting personal now.

Dave
 
Man I thought I had it. Read your instructions and started spraying the fine hose into that hole and barely any material was coming out the brass tube inside the side of the carb. I hit it from the other side hoping to hit that tiny little hole and I did and I heard a POP.... went back to the larger hole and low and behold man I was getting 8 feet out the carb with the throttle fully open. Hit everything else AGAIN with cleaner and mounted it up. Same damn issue. So I'm starring at the carb, pic attached. There are two brass tubes and the plunger rod protruding upwards. The one on the right has a hole that can easily be cleaned. The one on the left has a small hole but my wire cleaner stops about 1/32 into it. I don't see any hole in the side of the tube so what the heck is that??? Either I have a solid chunk of something or that tube is a mystery to me how it works.

Dang...so close. What this tells me though is your dead right about these carbs. Apparently I still have something somewhere.

Dave
 

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Good question..... you mean the rev limiter would kick in when the throttle is 3/4? Seems to me that the throttle should stop before the rev limiter hit but as you can tell....I'm a dang rookie here. BTW.... thanks for all the great recommendations and help here. It's really encouraging and amazing to me.

Dave
 
Man! You a much faster at doing carb r&r than most DIYers! It usually takes about a week to hear back on one of these!

And, I owe you an apology as I did neglect to have you check/clear the pump feed "tunnel" in the bottom of the float chamber..

Explanation: in the bottom of the removable chamber there are two tiny passageways that need to be clear. One of them feeds the accelerator pump chamber and the other I would actually need to refer to my carb manual to explain because it's been awhile since I did one of these. I believe it is a sort of vent to prevent hydro lock in the float bowl. Anyway, suffice it to say they both need to be clear. I've had to dig them out with tiny wire because they can be packed with "mud".

Also, you didn't mention the jet set and it's oring or if you backflushed the orifices in the top of the carb throat.

If you take it off again, make sure that you stick the spray straw into the main air jet entrance and push it inward as you blast away. Again, with the throttle propped open, you should see fluid coming out of all feed orifices at the top of the carb throat. The main air jet entrance is an approximately 3/16" drilled passage just above the carb throat on the carb's front mount flange.

The fact that you found the pump nozzle tube plugged tells me this carb needed the full "Monty" cleaning treatment and, even if it does turn out to be a limiter issue, your efforts and training have not been wasted.

I think that you're almost THERE.
 
I did pull that brass tube that has the O-Ring out and cleaned the 6 or so small holes as well as the jet orifice that sits horizontal. Some of your terminology is beyond my comprehenssion but I have sprayed in every hole, chamber, jet, orifice possible. I still don't know about that brass tube in the last pic I posted. One tube has a decent size hole and is easily viewable and to clean. The other, on the left, near the plunger rod, well my wire goes in maybe 1/32 and stops. No small homes along the sides so I'm not sure if I have a major obstruction or that tube does something I can't figure out. Yeah.... I'm hell bent on getting this done. With respect to the rev limiter, the manual says to adjust your throttle (on the tiller) to full and that should match to wide open on the carb. It is.

dave
 
The boat (with me has never been in water). Been using the ear muffs so the prop at least at this point is not the issue. Ironically though and your second point taken, I spent another can of carb cleaner and my air compressor and put it all back together. This time I used a garbage can (cleaned it good), and fired it up. I'm not going to say it's running perfect but it's able to run at full throttle now. Maybe it likes the trash can. Always had a solid piss stream with the ear muffs and the water was always cool. I think I'm just going to take it out and see what happens. I am curious though, I plan on running this up high in the Sierra's at about 6800 feet. My old 2 strokes I could get them to run at that altitude WITH adjustments. This carb has virtually no adjustments. Is it a smart carb?? (I made that up).

Dave
 
You should never try and rev an outboard at full throttle with no load, any motor will bark and carry on with the rev limiter trying to pull it back. I think you have done a whole lot of work for nothing
 
Well you call it work and I call it a learning experience. Hardly nothing. I certainly think that JGMO's recommendation of cleaning the carbs and especially the one that needs to shoot 8 feet (I don't know the names of these pieces) were well worth my time and efforts. It was just barely dripping out before I went at it and now it's blasting out. Certainly has to make things work better. I do appreciate everyones comments, recommendations and time. My thanks.

Dave
 
Yes, the accelerator tube being clogged was clearly a problem and made your efforts well worth it. Especially when you look at what I tell you next. I agree that "free revving" or going full throttle in neutral or with no prop (no load) isn't a good practice. I didn't realize that was what you had been doing so, yes, you were up against the rev limiter I imagine. Thankfully there is one!


...Honda offers two "optional" main jets for these carbs. See item 22 in the link below.

https://www.boats.net/catalog/honda.../bf15dk2-lha-2007-and-later/carburetor-manual

You can see that the "original" or stock jet is a #102 and the smallest is a #098 with a #100 between them. The optional jets are for operating the outboard at altitude. The original is used at sea level and should suffice up to around 3,000ft. After that the #100 might be selected and used up to and include 6,000ft with the #098 being selected for operating above that.

These aren't hard/fast rules and you may have to try.both optional jets in some cases to compensate for a rich condition due to a lack of atmospheric pressure.

Your new and hard earned carburetor repair skills will serve you well when you get into re-jetting your carb. ;>)

Like I said, it's been awhile since I worked on these but I have a couple in my barn that I can refresh my memory on about the two areas in your photo. Although, neither one is typically a problem area so that's why I don't recall thier names or exacr function from looking at your picture.
 
jgmo.... thanks again for the information. I ordered #100 and #98 as I'm right on that cusp of altitude. Also ordered some new intake gaskets, the o-ring I took off and inspected and a new impeller kit. Well you can see what I got. I'm new to outboards and certainly have taken a lump on this one but this boat is going to be real nice. Poor old guy only used it a few times over a 7 year timeframe. I was told 50 hours by his caretaker but his son says it's more like 10 hours on it. Bought the package brand new in 2011 out of Lodi California. Anyway, planning a trip once the snow melts hopefully in late May but I think that might be optimistic as they have a boatload (no pun intended) of snow. Those trout hopefully will be hungry.

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Well, I hope you catch your limit.

Kudos for getting the gaskets and oring. That can help quite a bit in many instances.

Normally I recommend the complete water pump kit but, in your case, the cup is probably in really good shape due to the low hours. Carefully inspect it for scoring and distortion and that it sits snugly in the plastic housing and doesn't "flop" back and forth because the plastic has been beaten out where the positioning tabs are.

Don't forget to reinstall the bigger jet if you go back down the hill. Running too lean at sea level raises combustion temperatures and can cause detonation.

Make sure that you completely run the fuel out and then drain the float chamber anytime you won't be using the outboard for more than a couple of weeks. This keeps mineral deposits from forming and will increase the interval between carb cleanings significantly.

Please keep us posted on your progress and success.
 
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[FONT=Verdana, Arial, Tahoma, Calibri, Geneva, sans-serif]Hello, JGMO, Morecowbell and other contributors, First thank you all of sharing your wisdom and problems with Honda engines. Your contributes has already now helped a lot even I have not succeed to fix my Honda yet. It's still has following, similar kind of problem than Morecowbell had. Please find a video where symptom are "visible" and more important "listenable": https://drive.google.com/file/d/1e1kd-pCa0_4f4K58wrcNKzD2SJPOjzZh/view?usp=sharing

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I bought last winter this Honda BF20D3 2005, former owner told me that the engine has inside old gasoline and that is why it does not run smoothly...well now I feel that there might be something more than old gasoline :-(. Naturally I have changed all gasoline to the fresh one.
I have been working according your great instructions mentioned earlier in this thread. I copied your recommendations below to help understanding what I have already done:


1. Make sure you're running the right NGK plug as they just seem to work better than the Denso's. YES, they are new NGK plugs (with spark gap 0.8 mm).


2. There is a black, rubber, "FUEL CHAMBER" mounted to the engine oil dipstick. That needs to be taken completely off and all liquid shaken out of it every so often.
YES, removed and cleaned. It seemed to be ok and there was not mud/water very much. I believe that is ok.

3. The carbs on these can be "boogers" to get properly cleaned and the little "jet set" tubes are prone to cracking.

YES, Jet Set tube (Jet Nozzle) was cracked, bought a new one (50 euro, Jee, that was really expensive) and replaced but no ANY changes.


4. If the accelerator pump nozzle won't throw a MINIMUM 6 foot stream of carb spray out past the open throttle plate, it's NOT clean enough.
YES, it will throw at least 6 foot stream of carb and I believe that the accelerator pump works well also with gasoline EVEN symptoms are guiding me to blame accelerator pump. When the carburetor was removed, I filled up the float chamber with gasoline and I saw when gasoline comes out of a tiny nozzle drilled into a small brass tube that juts out into the carb throat at the entrance to the Venturi. I'm hesitating little bit of amount of gasoline needed to identify that accelerator pump works properly. Anyway I cleaned up accelerator pump very carefully and same time I was wondering same thing what Morecowbell was thinking with the two brass tube in message which was sent: 04-20-2019, 01:02 AM with the picture. I could not found any function for the second brass tube but I believe it is closed and there should not be drilled hole inside (it's solid), right ?


5. Also, while you have the throttle plate propped completely open, you will be able to see and access ALL of the fuel feed orifices at the top of the carb throat. Use the spray straw to cover each orifice and back flush each, one at a time. This is best done with the jet set tube and idle mixture screw removed. You will see fluid coming out of the idle mix cavity when you hit the idle orifice and you'll see fluid flow from the main passage where the jet set mounts when you spray the transition and full speed orifices respectively.
YES, every orifices seems to be open. Even symptoms are guiding me again blame these orifices. BY THE WAY, motor is running(Accelerating) better if I "open" more than 2.125 turns out the idle mixture screw. In video idle mixture screw is opened 4.25 turns. What this tell to you? Motor have "automatic" choke and when the engine is cold choke keeps rpms higher and after few minutes (3-5) rpms comes down telling to me that "choking system" works fine.


6 I checked the float chambers float's height and it seems to correct (13.7 mm or 0.54 in) so I believe level of the gasoline is ok in chamber and also I checked fuel pump (removed gasoline tube and rotating motor by starter and verified pump is pumping gasoline, yes it does)

[FONT=Verdana, Arial, Tahoma, Calibri, Geneva, sans-serif]I'm stumped also and now wondering, is possible to have something wrong outside of the carburetor which is causing these symptoms? Ignition? / Timing ? Protection system? And yes motor is without load (water) but there is no attempts to have full throttle. Any help? all opinions are welcome and highly appreciated.










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Hi jarrko,
Whew! Did I write all of that? :>)

First off, I can clearly hear the exhaust so I'm guessing that you're running on muffs and garden hose.

The way it's responding to the throttle makes me wonder if it's running on both cylinders? That's what I would first check if I were there.
The Honda twins will start and idle surprisingly well on just one cylinder.

Take off each plug wire and smear a very thin coat of dielectric grease inside each boot. This makes taking them off and putting them back on the spark plugs easy while the engine is running. Do a cylinder contribution test by pulling one wire off and see what kind of difference it makes without that cylinder firing. Note the degree of change and then replace the wire then try the other cylinder. Wear thick gloves, use a dry rag or spark plug cable pliers to prevent being shocked when doing this.

If the engine quits as you pull a wire that is an indication that the other cylinder is not contributing as it should if at all.

Please try this test and get back to us.
 
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Dear jgmo, thanks for answering. I will do the test next tomorrow, and thanks also of your contribute to this problem. Honda is new for me and I don't know it well yet. Former engine was Suzuki without any difficulties but I wanted to change Honda due the great reputation and the fact that Suzuki get almost more older than me :). Greetings from Finland, northern part of europe. I'm fishing (amateur) western coast of the Finland near Vaasa city. Please take look of google map: https://www.google.com/maps/d/viewe...1&ll=63.09519490000001,21.58505070000001&z=18

Br Jarkko
 
Oh yes! I imagine it is very beautiful there. I know you are much farther north than I am. It is 100 degrees farenheit (38 c) here today and is getting "warmer" every day!

Once you get your Honda 20 running properly I know that you will love it! I have a 2006 BFD 20 myself and I have worked on many of the 2003 models in a rental fleet of boats. They received 0 maintenance for the first five years of life and they all ran great when I got hired to maintain them. They are very rugged and stand up to abuse and accidents better than any others I've been associated with.
Very reliable and trouble free if treated properly.

Parts are easy to get and not expensive over here but that may not be the case where you live I'm afraid. I was shocked to read that you spent 50 euros on a jet set!!! Over here it costs about $17 usd or less than 10eu! I realize your prices may be inflated due to shipping and possibly other economic "dynamics" but a 5 times increase seems very unfair to me.

You may want to look at boats.net for parts. They do international shipping although I'm sure it's expensive.

I tried to ship something to France not long ago and was very discouraged when I was told what it would cost.
 
That's pretty warm there, like it even it might be too much for me. Last summer was exceptionally really warm here too and I enjoyed :). Yes, I'm using garden hose with the adapter to upper part of the motor, so I don't have to use Mickey Mouse muffler. Today I tried your test and after few minutes I noticed that impact (taking the the cord off) varies...sometimes motor almost stopped and sometimes there was impact at all (within the same cylinder) so there was something which guided me to inspect the ignition coil. I used standard multimeter and the primary coil (input side) of the ignition coil is ok (0.8-1.0 Ohms) but the secondary side (Spark plug side) varies and it was really difficult to got decent measurent result... I think it should be 23.0 - 34.8 kohm and lowest measurement result was 0.8 megaohm. My multimeter is not Fluke quality but it has been so far pretty reliable...I even change the battery to new one :). Thinking to do measurement again with quality multimeter. Any thoughts ?
Br Jarkko
 
Question: can you give some history about your ownership of this outboard? As in; is it a recent purchase? Did it run better than this for you? If so, did this problem happen suddenly or gradually? Previous repairs other than carb cleaning and jet set replacement?

You may have stumbled upon an issue with the coil's secondary resistance but the symptom in your video doesn't look or sound like the coil "breaking down". And yes, if you can use a better meter to check it with, that's a good idea. Do the metal clamps that snap onto the tip of the spark plugs look rusty?

At this point, I would like to know about the tension of the timing belt and how the marks line up. I would also want to know if the valves are properly adjusted and adjuster screws secure.

I have the shop manual for the 20 so if you need specifications or direction I can look it up for you.
 
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