Outboard Woes - Anyone Know About Carbs ?

[Catpainzmcspice]

Hi! Since my yanmar inboard is on the fritz I thought I'd focus on my auxiliary-auxiliary motor. It's a mercruiser transom mounted 40hp outboard.

It starts with on pull. It idles a little high. But as soon as I put it in gear it dies.

I replaced the fuel pump and the filter. I've fiddled with the needle valves.

The only real success i've had is closing the choke half way. When I close the choke it runs for a few minutes.

Is the solution to pull the carbs and rebuild? Am I missing something simple?

Thanks for any input!

-alex

[Rakuflames]

Originally Posted by Catpainzmcspice

Hi! Since my yanmar inboard is on the fritz I thought I'd focus on my auxiliary-auxiliary motor. It's a mercruiser transom mounted 40hp outboard.

It starts with on pull. It idles a little high. But as soon as I put it in gear it dies.

I replaced the fuel pump and the filter. I've fiddled with the needle valves.

The only real success i've had is closing the choke half way. When I close the choke it runs for a few minutes.

Is the solution to pull the carbs and rebuild? Am I missing something simple?

Thanks for any input!

-alex

Has anyone used ethanol-laced gasoline in it?

[Catpainzmcspice]

Hmm... Good question. I bought the motor a year ago and the first thing I did was replace the tank and lines, buy new gas and a can of seafoam.

Will ethanol gas cause these problems?

[Svsilvergirl]

If it runs with the choke on , the main jet is prolly plugged

[Catpainzmcspice]

Main jet... Where is that located?

[Chief Engineer]

Get a manual....you will have to pull the carb,,,,disassemble....get a can of carb cleaner....it comes in a gallon paint can....soak all metal parts....blow out with air......spray carb cleaner will not work

[gunkylump]

Is it two stroke or four stroke? Did you run the whole can of seafoam through it? If you ran the whole can of seafoam through it, sounds like your main jet is probably plugged......often running seafoam through a motor for a while....a few minutes or so, then letting it sit for a day or so will clear up the issue...if it is dirty carb/jet related. Seafoam is relatively cheap, might be worth a try before your tear your carb/carbs apart. Doesn't sound like a fuel pump issue, you are getting fuel. Quite often running with the choke partially open/closed is a pretty good indication of plugged jets. Hope this helps, worked fine on motorcycles<grin>

gunk

[GordMay]

See the Outboard Motor Learner’s Guide
➥ http://www.spc.int/coastfish/Section...oard_lg_en.pdf

http : // www . spc.int/coastfish/Sections/training/fts_pdf/statutory/outboard_lg_en.pdf

[Catpainzmcspice]

Excellent! Thanks for the tips. I got it working, and it's better than ever.

I removed the two carburetors, unscrewed the jets and sprayed them with Orange Degreaser. Then I soaked them in stove fuel followed by gasoline and finally shot them with compressed air.

I thoroughly cleaned the bowls and blew out a ton of ancient calcified sludge and goo.

Then I reattached the carbs, connected all the hoses and fittings, primed the engine and it started in less than a minute!

It was immediately obvious that the problem was solved. I ran it up and down the ship canal and around lake union for a couple hours without so much as a hiccup!

Not too bad for a 1970s merc that I bought for a song and hadn't been run since 2003! (side note: the motor came with a junky 1957 Larson fiberglass boat as part of the deal, which I couldn't resist refurbishing a year ago, minus the outboard. $250 for the lot!)

Thanks for the help, everyone!

-alex

[Svsilvergirl]

Now that it runs , do yourself a huge favor . Before you shut it off , turn off the gas , and let it run out . It's the gas that gummed up the bowl and the jets

[S/V Antares]

your 2 stroke is less prone to E-10 (Ethenol) gas issues than the newer 4 strokes. If you store it over the winter use a stabilizer and drain the hose and bulb before you use the tank in the spring. E-10 or soon to be E-15 (15%) is a real issue. Some marinas sell non ethenol gas. Well done on trhe carb work.