Outboard Symptoms (help please)

[KingRichard]

Needle valve/float height - The float is often a separate part from the carb kit, at least in cars. If it's the foam type replace it, if it's brass or a other sealed type and not leaking then it works fine and just check the height.

Also, there is definitely some merit to the modern unvented fuel tank being the original root cause. A check valve or vented tank would help prevent a reoccurrence.

The project farm guy does some neat stuff. My guess, without watching, which I totally will, is he did not find seafoam to be snake oil, but rather some of the applications of it are better than others. Assuming he tested a few. Now that I think of it, you might want to decarbon your engine with it once you have the carb working. Use the process where you choke the engine out with it, wait 15 minutes and then choke yourself out with smoke...

[Tin Tin]

I gave up and just bought a whole new carb and kept the old one as a spare, they are not very expensive (or didn't used to be).


Any chance of accidental use of fuel with ethanol it it at some point? If so fuel system components may be compromised



If it is not the carb could be valve clearances need service, timing belt, fuel pump - there is a long list in the manual.

[hlev00]

On first symptom, yes it is flooding. On my Tohatsu 6HP I always disconnect my fuel line especially when tipping the engine up on the transom of the dinghy. Even so, it still seems to flood a bit. In this case I put the throttle wide open and start. Usually it starts on one or two pulls. If it starts to catch but not quite, I back off to 1/2 open throttle. Play with it a bit. And use, I usually have a good deal of smoke.

[SVJOCO]

Thanks everyone.

For the past few days of use I’ve ensured I unscrewed the tank cap to fully vent the tank, before starting. It’s firing up first pull or two, and without smoke.

I guess I’ve learned that modern fuel tanks not venting (except when running) can certainly be an issue without a demand valve / check valve in the line.

I’ll keep the needle valve & float relationship in my mind in-case the problem rears it’s head again.

Thanks again to all of you for your replies!

[pcmm]

Originally Posted by SVJOCO

I’ve never seen this on someones dinghy before. Is the use of one of these common?

Could you perhaps link me to one of these?

Thanks

Just leave the vent on the tank cracked open.

Some of these EPA ideas just break perfectly good systems.

[rslifkin]

Originally Posted by pcmm

Just leave the vent on the tank cracked open.

Some of these EPA ideas just break perfectly good systems.

Adding the demand valve is a better fix than leaving the cap loose (leaving the vent open doesn't release pressure on modern tanks). Less chance of leaks or getting water in the tank. Plus, as much as well sealed tanks can be a bit of a pain, they do have a big advantage on equipment that sees infrequent use. Gas that isn't being exposed to fresh air and evaporation all the time lasts a whole lot longer.

My dinghy hangs in davits with the outboard mounted and fuel tank connected, so my goal was a setup that isn't fussy. Just put the drain plug in, open the tank vent, drop the dinghy in the water and start it up.

[SVJOCO]

I’ve got an update for y’all. Though the motor has been running well, it came up with a new issue outta nowhere:

After running for a period (10 min approx) at full throttle, when I bring it back down to idle it holds a very fast idle. It doesn’t go away even if I leave it at that position for a few minutes.

Weirdly, when I pull the cowling to take a look at the carb, the idle drops down!!?? Happened twice.

Anyway I played with the throttle arm on the carb a bit tonight and I’m wondering if maybe the “return spring” (that’s what I’m calling it) is somehow related to the issue. All thoughts welcome, thanks.

[GreenWave]

Sure sounds like air flow thing. What else would change by removing the cowling? Any chance the spring is impeded by the cowling?

[SVJOCO]

Originally Posted by GreenWave

Sure sounds like air flow thing. What else would change by removing the cowling? Any chance the spring is impeded by the cowling?

I had a similar thought, but how could it - it has the original factory designed spacing! Nothing has changed in that regard.

[GreenWave]

Does the change happen as soon as you remove the cowling?

[hlev00]

It sounds like something is binding in the throttle. Have you tried keeping throttle at max with the cowling off, not necessarily with the engine running. That might be a follow on test.

[SVJOCO]

For posterity, the problem was ultimately where the metal throttle acceletator connector joins to the spring loaded carburetor throttle arm. There is a small brass connector that was rusted/corroded enough that it was not sliding well against the greater arm. Some Corrosion-X and elbow grease and the two components were able to slide past each other freely.

Thanks again all for the help!

P.s. In other news, just learned about spun props! Waiting for a new one from Grenada as I type this …