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Short video showing bad idle on Johnson 120 - Any Ideas?

S

SeaPair

Member
Hi all, not sure how I haven't been to this forum yet since I am always on this site looking at parts etc....but oh well, now I found it :)

I am hoping someone here can watch this short video and let me know your opinion on the cause of this idle while on muffs.
[video=youtube;bKAhe1QgcDY]http://www.youtube.com/watch?feature=player_embedded&v=bKAhe1QgcDY[/video]

About the motor (1987 Johnson 120):
-Compression is good at @ 130 on all
-Fuel is good and fresh
-Spark will jump 1/2" nicely on all wires
-Just changed primer bulb (wouldn't start with the old one)
-Cleaned out the jets on carbs (cylinders 2&4 have different size jets - not sure yet if that's normal ???)
-Plugs are from previous owner and appear to be hotter ones, they are NGKR BZ7HS10
-I am using my portable fuel tank since I know it has always been reliable.

VRO Leak?
I did notice recently that when I prime the gas line hard there is a bit of gas / oil that comes out of the top of the VRO unit, kind of a circle looking area right on top.

Stator Leak?
I also saw some grease looking stuff on the top of the power head that didn't wash off like normal grease. This is a greyish looking substance but maybe it is just grease. I now have the flywheel off and can't see anything like that on the stator but haven't taken the timer base off since I am not sure what I am doing yet or what to even look for.

History before I bought it:
Previous owner had this out a couple of times where it ran fine for awhile and then lost power or ran real rough after it warmed up.
He had to use the kicker to get in and just didn't trust it anymore even after he:
-Had carbs professionally rebuilt
-Bought and installed new VRO
-Went through all fuel lines and tank
-Bought new hotter plugs.
But he never did figure out the problem.
I have only tried to take it out once but it ran terrible at the dock so I didn't make it out.

I appreciate any help on this, I don't know if I should call this a misfire or what? and If I should even run it long enough to test coils, carbs etc.

I have also attached some photos of under the flywheel...I do not know how to test any of this yet and do not have a DVA adapter unfortunately.

Thanks in advance.

 IMG_7215.jpgIMG_7216.jpgIMG_7222.jpgIMG_7228.jpgIMG_7230.jpg
 
You have ignition problems !!-----Mark flywheel with TDC for each cylinder and check timing as per previous post.----Check to see if powerpack is firing more that one cylinder at a time as well.------Inspect the outer flywheel magnets ( possibly loose ) and fairly common.---------Post some more pictures of the under side of the flywheel.
 
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Some of the CU (87) models used an RPM limiting power pack designated as "CDL". When the RPM limiting circuitry goes bad the symptoms are often identical to your video.
 
Awesome, I am very glad I am getting some response here...thank you all.
I will go through and answer or reply to each and then add some more info at the bottom.

I didn't want to post the second video because it may confuse the issue I am having now with the issue it was having the last time I ran it.
But they may very well be the same I guess.

So here's the story in it's full...just in case something pops out at anyone.

1. Bought boat / motor from guy who told me the issues he was having with it and the work he had done (he got a new boat).
2. Ran motor on muffs to warm it up, seemed decent to me so I put it in water but it ran like crap so video taped a couple tests and brought it home.
3. Made long 11 minute video to ask for help...didn't get much help (other site).
4. Then decided to clean out the carb jets.
5. Started it up and got this new erratic idle.

I may make my posts too long at times..I apologize for that but always want to give as much info as possible.

So onto the replies:

Docksidemarineservices said:
Put a timing light on all the plug wires one at a time and see which ones are not firing while running.
Click to expand...

A timing light is on my "have to find it cheap and soon" list...I have never used a timing light before but know I need one these days.
I am getting a DVA adapter first I hope..then a timing light. Might try borrowing one soon though. Thank you.

kimcrwbr1 said:
There are a couple possiblities one being the upper crankcase seal, possible reed valve failure? Did the engine get hot if your firing on all four and compression seems good then it is fuel. You are correct do not run it until you figure it out. A quick test is put about three tablespoons of fuel mix in all of the cylinders and fire it off whilse watching the carbs if it spits fuel back out reeds are suspect. the trigger is probably just fine if it runs at all. Also look at the crankcase and intake good looking for cracks of blown out gaskets causing the crankcase to lose pressure.
Click to expand...

I need to know if the reeds would shoot gas out of the carb throat or out of the brass jets? And is there a test for the crankcase seal?
It is (or was) spitting out of the brass jets when I tried a test run for the only time...I have since cleaned out all those jets and as soon as I did I got this erratic idle and haven't checked again to see if it's spitting fuel there or not. I will attach the longer video of my test run day at the end of this post.
Thank you.

racerone said:
You have ignition problems !!-----Mark flywheel with TDC for each cylinder and check timing as per previous post.----Check to see if powerpack is firing more that one cylinder at a time as well.------Inspect the outer flywheel magnets ( possibly loose ) and fairly common.---------Post some more pictures of the under side of the flywheel.
Click to expand...

You sound like you are fairly sure this is what is causing it...I am actually hoping you are right since I am scared of the cost for reeds or crankcase work and will soon be able to test ignition parts on my own (hopefully). I will try to get the timing light soon and will post more photos of flywheel. Thank you

kimcrwbr1 said:
If at all concerned the vro pump is not working premix the fuel or run on a portable with premix at 50:1. Mark the oil reservoir level and see if the level drops once you get it running.
Click to expand...

I have never owned a VRO so have no idea what it's supposed to do or not do...I will definitely be inspecting all of that when I get it running and have added a bit of oil to my gas just as a precaution. I also attached a photo of where the gas or oil is coming out..it does seem like an odd place to put this circle thing so am hoping it's actually a relief valve for when people like me "over" prime their bulbs...so it won't blow a diaphram or something perhaps. This VRO was new around a year and a half ago and he was very cautious with fuel purchases etc. Thank you.

Haven't a clue said:
Some of the CU (87) models used an RPM limiting power pack designated as "CDL". When the RPM limiting circuitry goes bad the symptoms are often identical to your video.
Click to expand...

Would the power pack say CDL on it? I have another question regarding power packs that I will be posting here soon as well. Thank you.
Note: I just looked and updated this..my power pack says CD4/8L on it...and it IS not the one the parts book says I should have BUT is one that is on the list of packs that CDI says their newer one replaces...hope that makes sense. Again it's a whole topic I need to post about.

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Thanks again to all, this is why I really need to LEARN how to test things...I have many different ideas from you all right now.
of course I hope it's an easy and affordable issue to repair but I think it will be a combination of things personally...whcih makes it real hard for a newbie like myself.

Here is the video that I originally made the day I wanted to take it out for a test run.
It seemed to run like an outboard should on muffs (to my newbie ears), but once I got it in the water it sucked.
This video is quite long but I wanted to show all I could.

[video=youtube;nDLjwcH-xog]http://www.youtube.com/watch?feature=player_embedded&v=nDLjwcH-xog[/video]

grease-powerhead.jpgvro-top.jpgIMG_7220.jpgIMG_7221.jpgIMG_7223.jpg
 
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kimcrwbr1 said:
Stock plugs, check the fuel for water by draining the float bowls in a cup/dish the water will settle on the bottom. Never put anything thru the carbs without oil, carb cleaner and starting are fatal to 2 strokes. Do not play around with fuel mix add oil at a 50:1 ratio until your sure the vro is good (a bit of oil does not cut it). It sounded like it was overheating just because its pumping water you need to be able to hold your hand on the heads for a slow count of six after the motor has run for a bit if not the thermostat/s are stuck closed or there is blockage thru the heads? If you dont know what your doing ask questions first.
Click to expand...

Stock Plugs:
Not sure what you mean by Stock plugs?..does that mean I should buy those? I have read many others go with these hotter ones when they do a lot of slow RPM use (fishing), but really doesn't matter to me, I just want what works best .

FueL: The fuel is brand new high octane, marine stabil added, in empty clean portable tank and bowls were drained when I cleaned Jets.

Ask Questions First:
I do ALWAYS ask questions or do HOURS of research before doing anything that could possibly cause damage....that's how I even knew how to do the carb cleaner test and that's why it has taken me so long on this motor (I am scared to break something or cause more problems) :)

Carb cleaner / Starting Fluid Use:
So I shouldn't spray the carb cleaner to make it bog down to test fuel delivery?
Will premix gas do the same? I have a spray bottle of that as well. I know about starting fluid and have used it cautiously and sparingly by spraying pre-mix with a hint of starting fluid into cylinders when I need a kick start on the starting or test if it's fuel delivery problem. Don't know if the pre-mix will help lube the cylinders but I feel it's better than nothing...plus the fluid I buy "says" it has lube in it for upper cylinders.

Add Oil to Fuel:
It seemed to smoke quite a bit like it should and there is quite a bit of oil / gas coming out the prop area (exhaust) like my other motors have done in the past..if I add oil to this tank and keep the VRO setup won't I be just causing another issue with flooding it out / over oiling? the only reason at all I even worry about the VRO is because of the small bit of gas / oil coming out only when I squeeze the prime bulb hard....and my thoughts were a possible air leak causing it to starve for fuel but I am still thinking that circle I pointed at in the photo could be a pressure relief valve..waiting for someone to chime in on that. That would suck if the new VRO only lasted a season...he said it cost somewhere around $500 I believe.

Possible Over heating:
I didn't notice anything hot at all and I have no idea what an outboard sounds like when it over heats. Was that on the short video or long video that you thought it sounded that way? I barely even got it to run for more than a minute at a time so wouldn't have even thought it could over heat in that amount of time...next time I run it I will be sure to feel the head etc. Funny timing on this because I just got back inside from feeling an overheated 15 HP...the tell tail was peeing fine, I ran it for about a minute while I shot a video and when I went to take plugs out to check compression again they were HOT..I felt the head and oh yeah..it was way hot. That project was a fun one I will post about in the next few days when I get time.

Oh that felt like a lot of typing...lol Thank you for the reply.
 
Docksidemarineservices said:
Start with the timing light and DVA. Timing light first. Once you get it to run correctly you can investigate the rest of the engine.
Click to expand...

I am researching right now on what to look for in a timing light...do you have any suggestions or can you tell me what if anything is required, or are they all the same?

DVA can't be bought locally so I am going to have to order one...may order the timing light too but thought I should check pawn shops first around here.

Thank you.
 
All you need is a cheap timing light. No timing advance knob, no extras, just a light. I paid about 70.00 for mine.
 
Going on road trip tomorrow to see son (only son) graduate so won't be around for a while...got the DVA ordered and on it's way ($38 after shipping).
Had a cheap timing light in my shopping cart and almost bought it but decided to look up reviews..glad I did or I may have wasted the $16. Will just buy one of those locally when I get back next week.
Til then..thank you.
 
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