Help, boat stalling at idle and high RPMs

[AJFishin]

Today I took out my boat and it ran fine ,but after a couple of hours of running, I started to head back to the harbor.
When heading back I noticed when I would push the throttle forward the engine would end up dying at about 1700 RPM (Yamaha tach says"17") I limped back to the harbor at 1600 RPM as that was as far as I could push it without the engine stalling, and the engine was running very ruff and with excessive boat vibrations.
When the boat sat idle it would stall after about 30 seconds.  I would have to adjust the choke in order to get the boat not to stall when in  neutral.

Not sure what the problem could be?


What I did when I got home....
Engine has 3 carbs.

I pulled the carbs off and noticed on my lower carbs O- ring that is on the inside of the carb, where it presses up against the manifold, was cut in half and some of it appeared to be inside the manifold.
Another thing I noticed was my middle carbs pilot jet was clogged, so I sprayed carburetor cleaner in that it and cleaned it out. The others carbs jets were cleaned as well. I would assume the clogged pilot jet is the reason behind my bad idle?

Also when I was docked I swapped out my water separator/ fuel filter and my small fuel filter that is on the engine. After that I tried to run the engine over 1800 RPM, but it just wanted to stall.

Do you think these 2 issues (cut O-ring on carbs manifold and clogged pilot jet combined were causing my problems today?

Since I can't run my engine at high RPMs from the hose, I will have to wait till tomorrow to run it in the harbor. But  before I do that I wanted to know is there any other suggestions what it could be?

Thanks

[Sea Bear]

One more thing I would check is the snap fitting o-rings on the fuel line.  I have been going through them like changes of underwear this year.  I had a similar issue two separate times this summer, and it ended up air was getting in the fuel line.  So check your hose clamps and o-rings!

But is sounds like you don't have enough fuel coming in.  So maybe you have a fuel pump issue or sticky float valve in one of the carbs. 

In any case,  good luck tomorrow.  Gotta keep those 2 strokes humming!   :party:

[AJFishin]

One more thing I would check is the snap fitting o-rings on the fuel line.  I have been going through them like changes of underwear this year.  I had a similar issue two separate times this summer, and it ended up air was getting in the fuel line.  So check your hose clamps and o-rings!

But is sounds like you don't have enough fuel coming in.  So maybe you have a fuel pump issue or sticky float valve in one of the carbs. 

In any case,  good luck tomorrow.  Gotta keep those 2 strokes humming!   :party:

The "snap fitting o-rings" you're talking about on the fuel line is the fuel line from the filter to the engine which has the primer bulb attached?

I recently swapped out the fuel pump, but I'll bring my old one with me tomorrow just it case, since it still basically works.
Carbs where completely rebuilt last month but I didn't check the float pins today,  :hoboy:

I'm crossing my fingers for tomorrow it runs like it has been. I hate not being able to fish

[Sea Bear]

Yes. The snap fitting at the engine.  I always keep spares, since one little crack & she's sucking air.  Come to think, I had three things wrong with my fuel lines this summer. 

1. bad o-rings
2. bad clamp on the fuel line
3. cracked primer bulb

I switch my fuel line to the kicker when I troll, so that o-ring gets a work out.  What kind of tank do you have?

[Sea Bear]

Also check your plug wires to make sure they are securely plugged in, and in good shape.  Check the coils to make sure one hasn't developed a crack.  Both of these can cause your engine to cut out at higher revs.   :twocents:

[Ssericz]

Is it a 2stoke sounds like a limp mode is kicking in the stalling is from engine running too lean (too much air to fuel) cracked o-ring and plugged jet can do that

[StreamFixer]

Sea Bear

Were I you, I would be seriously thinking about replacing my entire fuel line.  If it is older, it is likely rotting from the Alcohol blended into the fuel.  The older rubber lines simply do not handle blended fuel well.

StreamFixer

[Sea Bear]

Sea Bear

Were I you, I would be seriously thinking about replacing my entire fuel line.  If it is older, it is likely rotting from the Alcohol blended into the fuel.  The older rubber lines simply do not handle blended fuel well.

StreamFixer

I haven't found a fuel line that holds up well.  I replace the fuel line last year & the primer bulb lasted one season.  Installed a seachoice black bulb, using the same grey fuel line from last year.  Local fuel stop has ethanol free gas here on Camano, but it's over $4 a gallon.  So I've been using the cheap stuff.  If it aint one thing it's two.   

[Threeweight]

I swapped out all my hoses for the gray alcohol resistant stuff from West Marine a few years ago, and used separately-purchased Moeller primer bulbs and fuel fittings.  No issues.  And I run E10 regularly.

I think the economical pre-packaged fuel lines are not so economical in the long-run.

[AJFishin]

Thank you everyone with your advice.

One or multiple things were the cause of the problem, which ever it was, it was fixed.

What I did:
Thoroughly cleaned all 3 carbs
Replaced the manifold O-Ring on the carb
Trimmed the fuel line that went to the water/fuel  separator filter (noticed a cut at the end)  tightened everything up.
Clean the spark plugs
Adjusted the carbs just a little bit.
Changed the water/fuel separator filter
Cleaned the mini fuel filter
Inspected the fuel pump and lines

After all of that last night, I took the boat out today and she ran flawlessly at WOT!

Again  I really appreciate all the help, thank you!

Sitting outside the break water doing some fishing.

[Markshoreline]

Well, there's a great trouble shooting guide!

Nice post and glad you got her running so quickly.

[Sea Bear]

 :party:  Glad you're up and running!  That's a good outboard you got there!   :party:

[AJFishin]

That Yamaha runs like a champ! Thanks for giving me the idea of checking the fuel hose clamps.