a sluggish 90

Just got a 17' hydra-sports seahorse 170cc with a 2008 BF90D with 20 hours on it.
The boat and motor sat for 5 years until I bought it 2 months ago.

Took it to a Honda service center for the recommended 20 hour maintenance along with a thorough going over due to the lengthy sit. As expected the fuel system was pretty gummed up had all the lines, filters separators cleaned or replaced as they deemed necessary. water pump as well. Diagnostic system did not find anything out of sorts.

Drained the fuel tank and filled with fresh 93 octane gas and took it out for a test drive this morning.

issue is that it runs perfect until I take it to wide open throttle, it quickly surges up to 3400 rpms and stays here for about 2 minutes then it slowly begins to rise in rpm until its where I would expect it to be. Note, this is only when under load, if I disengage the transmission it surges as expected, however as soon as the transmission is engaged it behaves as stated. I would expect this motor to push this boat around without breaking a sweat.

Any thoughts on what could be the problem here?

- Ken

Simple things first. Let's initially assume that it's not the motor but the fuel feed. Try that again only open the fuel cap to your tank. If that fixes the problem, then you have a clogged breather on the fuel tank. Clean it out with a piece of monofilament from a string cleaner, or a flexible wire.

If that does not fix the problem, then feel the pump up bulb while it is chugging. If it is partially collapsed, then you have a pinched fuel line or an obstruction on your fuel pick up tube in your fuel tank. Check the fuel line for any pinch and blow low pressure compressed air back through it (with the filler cap loosened) for a temporary fix. You made need to remove the pick-up tube to do a permanent fix.

If no partially collapsed bulb, try rapidly squeezing the pump up bulb a few times to see if that straightens it out. If so, you could have a malfunctioning check valve in the pump up bulb or a failing low pressure fuel pump.

Chawk - Thx for the suggestions, will give them a try tomorrow and report back.

What rpms do you get at full throttle?

What size prop do you have?

What is your frame serial number. If it falls in this range BBCJ-1000001~1006008, then you may have an issue with the ECU. Some of those units surged when the throttle was held steady between 2000 - 3000 rpm. Also, erratic engine rpm was noticed while accelerating in the 3500 - 4500 rpm range. One or the other or both may occur.

The solution is a new ECM. If you are in the United States, ask your dealer about Service Bulletin #61. You are well out of warranty, but they could ask Honda for some consideration (since you just bought the boat and it has been sitting). The worst that can happen is that they say no.

Your dealer should also check to see if it has the most recent low pressure fuel pump. Depending on the fuel filters on your boat and motor, it may have issues of fuel starvation at sustained high rpm operation (the engine starts to cut out...but if you lower the rpm, the engine will run fine).....Service Bulletin #66. Again, this is typically only covered by Honda if you are still in warranty....which in the US, for that motor, is 5 years.

Mike

How would I be able to determine what size prop?
I'll gather the serial numbers and post.

It should say on one of the prop fins or under the prop nut hardware. If it has been repaired at one time, the numbers may be gone. If you see any numbers , let us know what they are. They may be part numbers, and we might be able to figure it out from that.

Mike

BBCJ-1003779 - My local dealer is going to contect Honda and see if they will honor the bulletin.

Noted this on the bulletin itself, so I have my fingers crossed seeing how the engine only has 20 hours on it.
Out of warranty:Any repair performed after warranty expiration may be eligible for goodwill
consideration. Please contact Techline or your District Service Manager. You must request consideration
and receive a decision before starting work.”

Thx for the info guys, I'll check on the prop when I pull the boat out this week, the prop is what it came with so I doubt its been altered at all.

Despite the statement of potential eligibility for "goodwill consideration" post warranty Honda has denied the claim siting 8 years is too old even with only 20 hours run time. To think I was excited to own a quality Honda engine that was broke from the factory is seriously disappointing to say the least.

That being said I suppose I will buy the part myself and give that a go, is there any diagnostics that can confirm this is the issue? (although the symptoms do match the bulletin to the tee).

Not that I know of, unless the dealer can borrow one from another motor or their district service manager (if he has one).

Mike

Also, check the part number on you engine to make sure it is the old one.

It bothers me a little that the 'faulty' ECU can't just be reprogrammed to solve the issue. Regardless of how old it is, it was released with a flaw that can't be blamed on hours of use or maintenance. A factory flaw should receive a factory solution.

Ok got part number 34750-ZZ0-023 ordered. is it as easy as the bulletin says, couple bolts and a couple wires? Just take the old one off and put the new one on and go test it? Or is there some programing that has to be done?

No reprogramming. Two bolts and two connectors. That's it!

Hope things work out.

It would be nice (but not really necessary) if you have a printout from the dealer of the run history from the old ECM for your records, since that will all go away when you change the ECM.

If he used Dr. H, he may have saved one of the snapshots.

Mike

Mike

Prop info
Quicksilver 2038P19

new ECU installed, it fired right up, throttle seems a bit more responsive but I hardly took it above idle in the driveway with just ear muffs on. Will have to wait for the weather to settle down before taking it out.
Old part was 34750-ZZ0-013
New is 34750-ZZ0-043 (apparently supersedes 023).

19 pitch might be a little high on a 17 ft boat...but..... let's see what your full throttle trimmed out rpm's are before I jump to conclusions. I am not familiar with your boat or its weight.

The Quicksilver prop fits without rubbing on the lower unit? When I try them, they seem to rub where it goes into the prop shaft holder.

Good luck on your testing.


Mike

The details

Boat 2000 Hydra-sports seahorse 170cc / 30 gal tank supposedly 1390 pounds itself, though after some hull work I would say its a bit heavier, call it 1500.
guessing between myself 1 other person and gear add another 800 (yea I am a big guy and bud's are also).

2007 Honda BF90D serial BBCJ-1003779
per SB#61 ECU has been switched out

Prop Quicksilver 2038P19

Just returned from service center where the following was done
water pump kit
thermostats
valve set 16011-zy3-a01
fuel filter high and low
insulator
oring
racor fuel/water separator install

Fuel tank drained and filled with fresh 93 octane


Took it out for a test run after the ECU replacement sadly to find it does the same thing.
at mid trim, purrs like a kitten, punch it to WOT and it jumps up to 3200 rpms and stays there with bow up, once I trim it down to full down position, the nose will drop and then it slowley begins to accelerate until about 3800 rpms then it takes right off. I got it to 5k before I chickened out and pulled it back. 4.2k seems to be the sweet spot for this boat and load where it is up on plane and running about as fast as I care to go.

@chawk_man - Popped fuel filler cap off and no change, fuel bulb is not collapsing and there appears to be good flow through the fuel lines.

I just don't know where to go from here, I guess I can just figure its the characteristic of this boat to be slow out of the hole.

Sorry that the ECU is not working as expected.

I may be misunderstanding but from your description, it sounds like you are going to full throttle to get up on plain with the motor trimmed up..."at mid trim". Try doing your takeoff with the engine trimmed all the way down. If you are already moving at mid trim and you go full throttle and lower the trim at the same time, it will take some time for everything to take off as compared to starting off trimmed all the way down.

Also...I know you do not want to go faster than you have, but you need to find a calm day and smooth water to take it all the way to full throttle at least long enough to see if the prop is the right size. The 90 should get about 6200 rpm at wot.

Mike

went out today, its was entirely to nasty to run up the throttle to max, although I did note that today even as I trimmed the motor I could not get it to go over 3200 rpms no matter what I tried.

Question, What is Vtec and what does it do?

found an interesting youtube video yesterday dated 8/2015. Same Motor, Same size boat, Same symptoms . This gives a good representation as to what I am experiencing to the tee. The guy says he's ben to a dealer for service and got the same stuff done I had done, he then was going t send it to another dealer for a second opinion. I added a comment to his thread asking if he had any resolution yet, hopefully he will respond.

Check it out -----> Here http://youtu.be/JTUXMp_Fuys

I'll start by saying I'm no expert on your outboard and my comments are primarily about your VTEC question. I think it's a good one.
VTEC is the name given to Honda's system of "changing" or "adjusting" the opening of the valves while the engine is running.

Interestingly enough, the system is designed to increase engine power and efficiency for high speed operation. I can tell you that I don't know if it could be the cause of your issue but I will say that it IS a mechanical function that is supposed to take place in the near rpm ranges that you are encountering your problem. So....it DOES make me wonder???

You can find descriptions about how it works by Googling VTEC. Essentially, it uses an electronic solenoid to redirect engine oil to a mechanism that engages higher lift cam lobes to operate the valves at high speed and load. On an engine that has been sitting for so long it could be that the system might be sluggish because time and moisture have gummed up the works...so to speak.

If that's the case, a good "flush out" with any number of effective engine cleaning products and methods MIGHT restore satisfactory operation.

However, the system relies also on some other factors that should be checked. The ECM controls VTEC using information inputs like engine temperature, oil pressure, throttle position, rpm and engine load. It would be wise to ensure that all of the pertinent inputs are within "range" and are supplying accurate information to the computer before assuming anything is mechanically amiss.

Just trying to help and interested in seeing your successful solution.

Good luck

@jgmo - thanks for the reply, i'm an old school mechanical type (carburators and Points) these new fandangle electronic stuff get me all lost. I did read through what vtec does, just still out to lunch on how it works and if it could be part of the problem or not. your logic did exactly what I was hoping for getting people thinking about it.

@hondadude - got out a a calm day this afternoon and was able to get her to open up. trimmed all the way down is the only way to get her to go above 3200, I was able to get it to 5k steady. As I began to trim it up I saw it spike to 6k and rev up (without additional speed or surge). Figured it had trimmed up to high and lost propulsion (note I was not even trimmed up to the 1/2 mark). Ran this exercise a few times and the results were pretty steady, so I am going to say we're at 5k fully trimmed down, but it takes a bit of finesse and time to get there.


With regard to the youtube video linked above he responded saying the following ...
"apparently. according to dealer #3, it turned out to be a fuel problem - HP fuel filter needed cleaned. engine running sweetly now."

After reviewing the invoice for the work done by the shop I see they did replace the HP filter and O-Ring.

So I presume this takes us back to fuel as a likely suspect as well as potentially the prop?

Could someone define "prop slip" ?

Thanks everyone
- Ken

I am not sure if this definite is totally accurate, but prop slip is a ratio of theoretical speed to actual speed. Theoretically, a 19 pitch prop will move 19" through the water with each rotation. Actually.....it will be something less. Indicating that the prop is slipping.

One other thing you can try, if you feel that the problem is a fuel problem...

Remove the hoses from the low pressure filter and connect them together (bypassing the low pressure filter) and connect them together using a double male fitting. This will take a little resistance out of the fuel route. If your motor did not have the updated ECM, it probably does not have the updated fuel pump. The symptoms that I have normally seen is that the engine, under heavy load at full throttle, comes almost to a stop....but will continue to run ok when the throttle is pulled back. The bypass that I described is something I had our customers do until Honda came up with a fix for the fuel pump issue.

My gut is telling me that it will not help, but it is worth a try. At least it is cheap.

Now for the getting on plane. I am still questioning how you are able to use a Quicksilver prop without it rubbing inside the propshaft holder. With the motor turned off and in neutral, turn the prop by hand and make sure that it is not rubbing. My experience, if the prop nut is tightened properly, the prop will not spin without a lot of effort.

Make sure that the horizontal fin above the prop is in the same plane as the bottom of the boat(even with the bottom). If it is lower than the bottom, it will be hard for the boat to get up on plane.

For that weight of a boat, you might have to drop down to a 17 pitch. It would be nice if you could borrow one from a friend to try it.

A 17 will get the boat up much faster....just have to watch the top end. Also, when I said fully trimmed, do not watch the trim gauge. Once on plane, trim a little at a time. The rpms and the speed should both go up. When the speed does not go up any further, you are fully trimmed.

Also, if there is any way to move some weight to the front of the boat, that might help getting up on plane.

Just some thoughts....

Mike

I am not opposed to trying another prop (I need a spare for emergencies anyway) what brand do you recommend? do you have a Part number I can reference?

ks3ct860 said:

I am not opposed to trying another prop (I need a spare for emergencies anyway) what brand do you recommend? do you have a Part number I can reference?

Click to expand...

Solas Honda
BFP60A, BF75, BF90, BF115A

Propeller Dimension
B D P R Honda Part Number
3 13 1/4 17 R 58130-ZW1-017AH

What do you think about this?

That prop should be fine. Only potential issue may be that it should take a different thrust washer than the Mercury prop. I am still wondering how the Mercury, that you have on it now. fits.

i would not want to drop the pitch too much. The 17 may be just enough to get it up and going and not overrev.

Don't forget to try the low pressure fuel filter bypass before you spend too much extra money.

This is where working with a local dealer helps. Sometimes dealers will let you return the prop for another if it does not work right for you and you do not mess up the prop. You have given them a lot of money for the service and degooing the motor, etc. They may even have a used one sitting around.

Mike

Don't forget to try the low pressure fuel filter bypass before you spend too much extra money.

do you happen to have an diagram showing where this is?

#9 is the low pressure filter. http://www.boats.net/parts/search/H...Later/BF90DK0 LRTA/WATER SEPARATOR/parts.html
It is located at the top port side of the motor.

Remove the fuel lines from the filter and join them together with a 5/16" to 5/16" barb fittlng like this one. http://www.ebay.com/itm/Free-Shippi...e-Barb-Splicer-Mender-Connector-/221863864449

Just do this just long enough to test. If you do not have an external water separating fuel filter, the only thing doing any filtering is the high pressure filter.

Mike

Thanks so much, just to be clear is this the part I am going to bypass?

I have a 17 foot Arima with a 90 hp and use a 15 pitch prop. The hull weighs 1250 dry. The hole shot is very strong regardless of load and hits 6200 rpm with ease. A 17 pitch works however can be a bit sluggish with load although certainly nothing like you describe. Ken at propgods is very experienced and could give you some good advice. It maybe that you have a mechanical issue as well however 19 pitch seems like a lot to me.

Yes, that is the part.

Mike

Just wanted to quickly pop in here and thank everyone for the help and suggestions, cold weather snuck in a bit early here in New England and I decided to pull the boat out while I had a few nice days left to get it ready for winter. I'll resume the troubleshooting in the spring.

Thanks again for all the input.

Ken