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Need help with Honda 135 Outboard (Struggling around 3k RPM)

bumblebimmer

New member
Hello Everyone,

We have recently purchased a 2002 Bayliner with a Honda 135 Outboard. Previous owner states it only has 25hrs on it and since it has been siting for a while did the following: Replaced rotten fuel lines, hoses, clamps. Replaced leaking fuel tank sending unit. New spark plugs, fuel filter, water separator filter raw water impeller, lower gear lube, pressure tested all the seals. Engines idles great, runs fine at low RPM however it starts to struggle around 2.5 to 3k and will not go faster than about 8 knots. We went ahead and replaced all the fuel filters again, replaced a total of 3 filters. Still struggling. Not sure what we should do next. After talking to some folks they suggested to clean the VST and go from there. I am not even sure where to find this unit and how to clean it. Any help is greatly appreciated.
 
Hi,
I'm not the resident expert on Honda fuel injection for this Forum and I've never disassembled a VST. But I thought that you could use this parts page link to identify it.

https://www.boats.net/catalog/honda...ge/135hp/bf135a4-la-2004/vapor-separator-assy

It would seem that the outboard is somewhat newer than the boat since 2004 is the oldest model listed and that was the year I copied the link from. If you want to date the outboard then you will need to refer to the FRAME number sticker or possible documentation that you received from the previous owner.

I do think that the fact that the engine was sitting does make the suggestion to clean it out a reasonable idea for sure and I know that many owners have done the job themselves.

Hopefully the "big guys" that know this stuff well will answer you soon with some better guidance and wisdom.

Good luck
 
Hi,
I'm not the resident expert on Honda fuel injection for this Forum and I've never disassembled a VST. But I thought that you could use this parts page link to identify it.

https://www.boats.net/catalog/honda...ge/135hp/bf135a4-la-2004/vapor-separator-assy

It would seem that the outboard is somewhat newer than the boat since 2004 is the oldest model listed and that was the year I copied the link from. If you want to date the outboard then you will need to refer to the FRAME number sticker or possible documentation that you received from the previous owner.

I do think that the fact that the engine was sitting does make the suggestion to clean it out a reasonable idea for sure and I know that many owners have done the job themselves.

Hopefully the "big guys" that know this stuff well will answer you soon with some better guidance and wisdom.

Good luck

Thank you for your reply, appreciate the info and link. I will dig into the parts page and see what I can find. From what I've gathered thus far is that this engine is pretty much identical to the Honda 150, I could be wrong.
 
Yes, I believe that you are correct. The shop service manual for the 135 and 150 combines both together.

Here's another link that you may find useful if you're going to be the mechanic:

https://publications.powerequipment.honda.com/marine#

Scroll down and select the high power service manuals then scroll down to the 135/150 manual.

Good luck
 
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$126 may be a good investment, thank you thank you!!!

Plan to do what we can ourselves. I have some basic auto mechanics skills, although boats are new to me.
My car is easy as it has all the sensors to tell me what is wrong, this 135 looks like a car engine but different. Either way I will need to learn and familiarize myself with it and a shop manual is one way to do it.
 
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Yes, these are the official Honda shop manuals and are really essential for anyone working on these outboards. They contain the most accurate information compared to the "knock-off" manuals printed by Sealoc, Haynes, Clymer and others and are well worth the investment. They will even hold a fair amount of resale value if taken care of and are a good "cherry on top" to offer if you want to sell your outboard.

If you're comfortable working on cars then the outboard shouldn't be something that would intimidate you. After all, I think a few of the larger Hondas are based on their automotive platforms.

Having the correct information and buying (or fabricating) a few special tools along with checking in with some of the knowledgeable guys on this site should get you through most jobs.

I recommend "tooling up" in order to be able to check your fuel pressure since all FI engines are sensitive to that and checking pressure is a basic troubleshooting step for almost all poor running issues.

You probably should wait until you get some input about cleaning the VST because there are a couple of things that can trip up a first timer...or so I've read.

Good luck.
 
Just pulled the code as a start. 1 long blink and 4 short blinks. Trouble code manual says ICV (Idle Control Valve) could that cause the symptoms we are experiencing? Currently the engine seems to idle fine, can't really tell from the gauge but just below 1000rpm, the range should be 750 +/- 50 rpm. Thoughts?

Also tested the fuel pressure, it was 43psi, which seems to be in range.
 
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No, that is probably an old fault. As I mentioned previously, start with a fuel system service, old fuel is extremely problematic.Also do a compression test
As a general rule, if there is no alarm, then there is nothing wrong with t he did system.Because this motor has Sat for so long, cover ALL the basics first, keep it simple
 
Tested the fuel pressure, it was 43psi at idle, seems to be within range. If fuel injectors were faulty or clogged wouldn't the fuel pressure read higher than normal?

Compression was done at the shop when they did the maintenance.
 
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Not at all, fuel pressure regulator controls pressure, there is no way of checking installed injector flow, you can only diagnose a leaking injector nozzle by seeing if the system holds pressure after cycling the fuel pump
 
Not at all, fuel pressure regulator controls pressure, there is no way of checking installed injector flow, you can only diagnose a leaking injector nozzle by seeing if the system holds pressure after cycling the fuel pump

Got it, we'll have to get new injectors. Took it out again today after checking the fuel pressure and my brother added octane booster, it's actually running worse now. Struggles at times. Wondering if too much octane made it worse.

Ohh and it also does the same in neutral, hesitates around 3k rpm, I we figured it's not the proppelor. Correction, in neutral we're able to bring it up to 4.5k rpm no problem.

Prop we got on now is 15.25 x 15
 
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New Injectors are on order. Hate to just throw parts at stuff without doing proper diagnosis. Honda Repair Manual does not point towards injectors. We tested them per the procedure as instructed in the manual and it all checks out. Tested the fuel discharge from the pressure regulator and only got about 18ml of fuel (manual states it should be 45cc or more). If low check all the fuel lines and pressure regulator. All the lines are new and we tested the regulator, both check out. Only other thing the shop manual states is the High Pressure Fuel Pump, again based on the shop manual. Any other way to test the HPFP?

Also just remembered, when we did the high pressure filter I don't recall seeing a spring. What does that spring do?
 
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Not at all, fuel pressure regulator controls pressure, there is no way of checking installed injector flow, you can only diagnose a leaking injector nozzle by seeing if the system holds pressure after cycling the fuel pump

New injectors are in, still having the same problem. Can't go past 3k rpm at 8knots, engine starts to struggle. Do you know what the little spring do inside the high side fuel strainer? When we replaced the filter we did not see a spring. Didn't realize one should even be there until looking at the repair manual. Spring I am talking about is part number 16913-ZY3-000
 
That spring provides pressure to keep the fuel strainer securely engaged to the nipple in the housing. If left out or improperly installed, the strainer cartridge will bounce around inside the housing. That could very well upset the flow of fuel and even block flow at times. Might be part of the problem.

Good luck.
 
That spring provides pressure to keep the fuel strainer securely engaged to the nipple in the housing. If left out or improperly installed, the strainer cartridge will bounce around inside the housing. That could very well upset the flow of fuel and even block flow at times. Might be part of the problem.

Good luck.

That makes sense, I can also see how this might cause an intermittent issue. I wasn't there to see it, but apparently the problem was fixed. Ignition switch was the culprit. Which doesn't make any sense to me. Could that have caused issues we were experiencing?
 
Well, I would be skeptical too about an ignition switch causing your engine to "bog down" consistently like it was....but....and I say it regularly....
....ANYTHING is possible.

If it's running as it should, about all l you can do is use it and see how she behaves.

Heck, it COULD be that resistance in the switch was having an adverse effect on volts going to ECM or main relay or both. That COULD affect the way the fuel pump was operating. Makes a good story anyway.

But, having said all that, I wouldn't be surprised if the condition returns.

The proof's in the puddin' as they say.

Good luck.
 
Got further clarification today, it was the kill switch not the ignition. While fixing the lights on the gauges it was noted that the kill switch was all corroded. Cleaned it and now she gets up to 30knots, still feels like it can go faster however. We'll have to see once we get the spring installed.
 
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