I have replaced the fuel lines, fuel pump, fuel filter, primer bulb, inspected the fuel pickup in the tank, had carb apart, found nothing wrong except a so so looking O ring on the main jet, which I replaced...


It will still run from an idle up to WOT and stay for 10-30sec and nose over and die, then start right back up. If you squeeze the bulb periodically while running it runs perfectly. Also the fuel bulb will pump up and get firm like it's supposed to while at idle or while the engine is shut off, but anything over an idle, it's mushy.

I did find my oil filler cap to be cracked and was leaking oil (and engine vac) my thoughts are this. When at WOT, you have at or near zero engine vacuum. If you're crank case is not sealed up the fuel pump will not work properly, which is possibly why it will start, idle, and run beautifully up to 3/4 throttle or so... But not WOT. I'm assuming with a vac leak on the crank case it can't move enough fuel to keep the bowl full.... I'm just trying to think a little more in depth since nothing else has worked at all.

What size fuel line are you using?

Maybe try cutting fitting off the end of hose and stick it directly in the tank. The pick up may be restricted a little and not fully clogged.

Fresh ethanol resistant 5/16

The thing that really doesn't make sense to me is, it just started this one morning out of the blue. Not gradually... I hadn't done any work or had anything apart prior to this.

Did that yesterday. Took the fuel hose off the tank fitting, took the cap off and stuck it right in the gas... Accomplished nothing except spilling gas on the floor running over some choppy water lol....

Well hell. Buy a new engine:lol:

I'm on the verge of putting a new carb on this thing...

The insides of this one are spotless, no residue, no torn gaskets etc... Like I said the only thing I found was the main jet O ring to be a little flattened. I replaced it last night and fixed the leaking valve cover. Also found a stripped valve cover bolt, tapped it for a 1/4-20 bolt and put on a fresh gasket. This isn't like a vanguard, it only has the one bolt in the center of the valve cover. It had a minor oil leak, I'm guessing due to the stripped bolt...

Gonna give it another whirl today after work... Who knows. I also have another tank to try. It's a 10gal aluminum tank out of another boat I had. It has an aluminum siphon tube and replaceable screens in the bottom. It's a better setup than this 6gal plastic job anyway...

is your tank vent open?

Tank vent is open... Wouldn't have made a difference when I did it with the cap off and the fuel hose hunt off in the tank. I went so far as to pull the tank vent all the way out of the cap.... No change.

Just a thought that came to mind. Check and make sure flat in bowl is adjusted correctly. If its bent up to high then the amount of fuel in the bowl is to low when the higher demand for fuel is there.(under load). Might try lowering float so the amount of fuel into bowl is increased. Just pulling ideas out of my ass now. Hope it helps.

I thought about that the first time I had the carb apart. I don't see a way to adjust it unless I were to just bend the tab that it mounts on.

As far as pulling ideas out of your ass... My ass hurts from pulling so many ideas out hahaha. I'm pretty much out of them.

Bending it is how u adjust it.

Gotchya... I may do that today before I run it. Never messed with a carb this small much. I know what I'm looking at but most that I've messed with have a threaded adjustment on the float needle to change where it is in relation to the float. That's how you adjust it.

Is the fuel tank in the bow? Maybe try adding an electric fuel pump if the float adjustment does not take care of it.

Fuel tank is in the rear. If I do end up adding the aluminum tank, I'll put it up front.

You have fuel/water separator? I just got my motor out shop. Where lines all go in was corroded and filled with rust flakes. Reckon it came from being in salty environment and uncovered. Motor was basically drowning. It would run like top in yard but minute under load nothing. Also, check plugs if it hasn't been mentioned.

Well, that didn't fix it either.

Going to try adjusting the carb float tomorrow...

No separator. Plugs are fresh within the last couple weeks... Changed them when I started having all these issues

seems this thread is stuck in fuel problem mode - could it be ingition related? I had an outboard that did this and it was the coil/power? pack.

Considered an overheating coil or a bad coil harness/diode...

-but that wouldn't explain why you can squeeze the fuel primer bulb and the engine will take off and run great! Gotta be fuel...

Considered an overheating coil or a bad coil harness/diode...

-but that wouldn't explain why you can squeeze the fuel primer bulb and the engine will take off and run great! Gotta be fuel...

Don't see any mention of replacing fuel.


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Fresh 93oct... Twice.

Took a break from it today and worked on my bike a little. Gotta get it back in shape for riding season now that duck season is pretty much over. Put the new clutch basket and all together and started on the new front forks, gonna be sweet!!!

You gotta an air leak in the gas line somewhere, on one of the fittings... Crappy gas tank quick connects will cause this as well but I see you've eliminated that.

Take a small length of new fuel line and hook it directly to the fuel pump and put the other end directly into your tank. If it does the same thing, you've at least eliminated everything from the gas tank to the fuel pump.

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i run electric fuel pump on mine

I don't need an electric fuel pump... It's ran fine like it is up until about a month ago. I just need to figure out what's wrong with it lol. I don't want to rely on an electric pump anyway.

fuel pump may be going out just put a eletric on to see if thats the problem

or spark plug wire arcin out or a loose fuse

Plug wires have been taped and are in good shape otherwise. I've looked all over the electrical system and even gone so far as to squeeze the fuse holders with needle nose pliers so they're goodntite (that's a word) I know it's a fuel delivery problem without buying an electric fuel pump. When it stumbles on the water squeeze the primer bulb and it'll take off... In other words... Yeah, it'll run with an electric pump on it but I'm not going to put an electric pump on it to mask a problem elsewhere... Last thing I'm gonna do is try adjusting the carb float.. After that I'm out of ideas... Intake gaskets, carb gaskets, plugs, plug gap... All good... Wtf...

sounds like your factory pump has a busted hose maybe or its going out

Remove the bulb completely. Try that, you'd be surprised.


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i run a electic because my tank is in the front of my boat and my factory pump wont pull it when i have a heavy load i dont run it unless im hauling a load of brush

GD- Guess you missed the part where I replaced the pump and every piece of hose on the engine...

I have thought about removing the bulb. Guess I'll do that next time out if the float adjustment doesn't cure me.

I just suggested to a buddy with a 25gdlt that has same issue to replace primer bulb cause his falls on face and he pumps it up and it takes off. I ask him if his fuel primer ever pumps up till its hard he said no. (No.sexual jokes please)(I thought about.how that sounds already. Bad) he squeezed the primer in my boat and was rock hard. I think his check valve is broken or missing. He's going to try a new one. Might give it a try. Just sayingq

The old primer I replaced was just getting stiff in general. Hard to squeeze even when disconnected. The rubber was old I guess. The new one feels way mushy in relation. It will pump up and get firm when the engine is off but as soon as it's running you can mash it flat without really putting much of a squeeze on it.

Take it off completely


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Sounds like you are getting air into the fuel system. Check all hoses and recheck fittings. Put an inline filter as close to the engine as you can. Get one that is clear and see if there are air bubbles coming through the fuel line when WOT.


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Thanks for your input but wouldn't you think looking for air bubbles in a clear fuel filter would be about the first thing I'd do? Look at the symptoms and ALL the testing and diagnosing I've done...

I agree, it acts like an air leak but I'm pretty sure I've already eliminated that by replacing and double checking basically everything between the gas pump and intake valve that has to do with fueling... Minus a float adjustment. I will try deleting the primer bulb all together to see what that does also. I'm just afraid that if I do that I'll have to wind on it to get it to start if it sits for a little while.

Have you replaced the filler cap yet or epoxy the crack back together or something? I know you've change everything but its either an air leak somewhere, the pump took a shit, or you're not getting vacuum for the pump to work. If it ran fine before how would something on the inside of the carb bend itself all of a sudden and get out of whack? I think it's Got to be outside of the carb...

Main reason I went in the carb was just hoping to find something with some trash in it. I agree, it's been running fine as it, why even back with the carb float? It's worked fine for literally years where it's at.

What crack are you talking about??? I haven't replaced the fuel cap no. I did run it with the line directly submerged in the gas in the tank though. That would rule out a bad cap, vent, tank fitting etc...