'77 Johnson 35, Not Starting Today

[Tallahatchie]

I've had this motor for about 8 months, it has always started right up and runs like a new one. Yesterday I launched, cranked it, it ran for about 20 seconds and then shut off. Would try to run for a few seconds then die, finally would not run at all. At home on the muffs I have gotten it to crank and run a few times for from 5 to 15 seconds then it chokes out and dies. Here is what I have tried so far:

1. Checked spark, it's good on both cyls
2. Compression was 120 on both cyls last time I checked (not today)
3. Sprayed pre-mix into carb and it will crank for a few seconds
4. Fuel pump was replaced a few months ago
5. Checked tank and hoses, bulb seems to be holding pressure
6. Checked outlet from fuel pump to carb, it is spraying a good stream
7. I did add 3 Gal. of fuel before the trip from the store where I always
buy my ethanol free gas, never had any problems with their fuel.

Does this sound like a carb problem? Can a carb be working great one day then not work at all the next?

Thanks, I appreciate any help.

 

[HybridMX6]

Re: '77 Johnson 35, Not Starting Today

If spraying pre-mix into the carbs makes it run for a few seconds, it's going to be a carb issue. All it will take is a little piece of debris to block the idle or low speed jet, and then it won't start. Could be as simple as when you got gas a small piece of debris was stirred up, and it made it's way to the carb. If it's been a while since they were last cleaned, I'd go ahead and do a rebuild on each with new kits, 99.9% chance that's gonna fix your problem. I'd also consider replacing the fuel line and bulb if they are old, could be some gunk trapped in there as well.
Is there a fuel filter on the engine at all, even an inline one? I'd also pull the fuel pump apart and make sure the screen filter is in good clean condition, just to be sure while I'm doing the carbs.

 

[Tallahatchie]

Re: '77 Johnson 35, Not Starting Today

Ok, I guess I'll do a carb job. Might try replacing the fuel line and bulb first just to see if that may be it, the bulb doesn't seem to be holding as tight as it once did. I do not see any inline fuel filter other than the mesh screen on the end of the fuel hose in the tank, and it does not look to be clogged.

 

[Tallahatchie]

Re: '77 Johnson 35, Not Starting Today

I found the problem, it's that long piece of rubber stuck in the fuel line and another piece that was sucked up into the needle seat. I don't know where in the world these came from, they were thin red ribbons of rubber. Looks like gasket material from somewhere maybe the fuel pump. I went ahead and rebuilt the carb, got it all back together and she runs great! I added a fuel filter between the fuel pump and carb (See photo) to try and keep anything else from being sucked into the carb. This is a fuel filter I had laying around the shop, I think it came off a 4 stoke gas engine. My question is will this filter be Ok to use on the 2 stroke motor, I don't want it to filter all my oil out of the fuel. Is this filter Ok or should I get one made for an outboard?