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1984 Evinrude E30 stalls

P

pwskicat

Regular Contributor
Don't have serial or model # handy. Hope someone can help anyway.

Two-cylinder, single carb. I have owned this engine for 5 years, and, up 'til now, it has given me no trouble. Now all I got is trouble. Two tow-ins from the middle of the lake this season.

Symptoms:
Idles rough.
Dies on throttle up.

What I could see as of last night:
Fuel line pump bulb won't stay hard. (Is is supposed to?)
Fuel residue in carb throat.
Fuel flows freely from bowl when screw is removed from bottom-front of carb.
Fuel pumps from line when disconnected from fuel filter.

What I've done:
Professional mechanic carb rebuild.
New gas tank and tank line.
New fuel, Marine Stabile and Evinrude oil.
New fuel filter.
Removed deteriorating foam from inside of cowling when mechanic found a what may have been a piece in the carb. Thoroughly cleaned cowling.

There is no *&%#* air filter on the carb (What idiot engineer thought this was a good idea?) Seems it's just sucking up garbage and I'm paying the price for bad design.

Many thanks for your help, PW
 
No need to slam engineers.----------------Outboards do not operate in a ( dirty environment ) and have not had air filters for eons.--------Only the latest greatest new motors are starting to use filters.----------------Do a compression test and report the results !-----------Check that you have spark on both cylinders that will jump a gap of 7/16".--------------These are the " must do " first steps in trouble shooting. Has the waterpump impeller been changed while you have owned the motor ??-------Fuel bulb does not have to stay hard as most people mistakenly believe.
 
Will do as u suggest. What is compression spec? How do I do a spark test over 7/16"?!? Only prob I've ever had w/this motor has been fuel related. Right after carb rebuild, it ran like new ... for one trip around the lake. Second trip, had a little trouble getting it to throttle up. Third trip, towed in.

Bought a brand new Yamaha 85 in 1987 an it had mesh hats on its 3 carbs. Only had to clean carbs out once in 12 years. One very small piece of debris can plug a jet. If I was the outboard king, they's all have some kind of air filtration.
 
Did your " mechanic " check for debris in the reed valves ???----Debris in the air going into a carburetor will never " plug a jet "
 
I'd appreciate a polite conversation. The mechanic I use runs a mobile marine service and has done right by me with other boats. Anyone can make a mistake. If u want to play the rude/sarcasm game, go "help" someone else.
 
OK. So ...

A) How do I do spark test you suggested. I have no experience at making a spark jump a 7/16" gap.

B) How do I check reed valves?

Many thanks for your help, PW
 
Well you can use a proper spark checker with adjustable gaps.----------You could make something like that with some sparkplug wire and a piece of plywood.----------Just cut the wire and staple it to a piece of plywood so you have a 7/16" gap or there abouts.----------Stick one end into the spark plug boot and put the other end to ground.------Reed valves are behind the carburetor.--------If any debris gets in there to hold one open then you lose crankcase compression on one cylinder.----------Loss of crankcase compression does not affect cylinder compression.
 
Many thanks to racerone for putting me on the right track. His comment, "Debris in the air going into a carburetor will never " plug a jet "" cleared up my misunderstanding of how a carb works. After doing comp test (80 psi exactly on both cylinders), spark test (good) and fuel pump test (good), I took apart the carb for the 3rd time this season and found a 1/8" chunk of what looked like fiberglass insulation stuck to the bottom of the fuel feed tube for idle and high-speed running circuits. I'd found the same crap both other times I'd taken apart the carb (crytalized fuel???). That's when I realized that whatever it plugging the carb was getting in AFTER the fuel filter. I installed all-new fuel lines and fittings after the fuel pump, and now the engine runs great. I put Stabile in every ounce of gas I use in the boat as soon as I buy it. Not sure it I trust it anymore. I need to figure out how to evacuate the entire fuel system at the end of every season.
 
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