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15hp evinrude wont stay runnin!

J

Joe69

New member
Hello! New to this forum. I have a 1986 evinrude 15hp short shaft that came on a duck boat. I ran it for two long days when i got it and it worked beautifully. The third time i took it out is started, but wouldn’t run much above an idle, but we putted too and from out hunting spot. At the end of the day, i looked around and thought I saw bit of black coning out of the fuel line at the fuel pump, I thought that the hose was falling apart because I used gas with ethanol. So I got new fuel lines for the engine and a small, in-line fuel filter for the quarter inch line between the fuel pump and the carb, as well as a filter on the hose from the tank to the engine. The next time I went to use the boat, it ran briefly, still had trouble at anything above an idle, although started to fly if I pumped the ball while it was going. Then later that day we had to paddle two hours back because the engine wouldn’t start at all. So I replaced the fuel pump, thinking that’s why it was starved for gas and stoped running, because I must’ve ruined it using ethanol fuel. Now there’s a brand new fuel pump, brand, new fuel lines. I can get the engine started, but it won’t stay going for more than two or three minutes, I’m running it in a test tank. Any help would be greatly appreciated.
 
1) No fuel filter is needed between the pump and the carb. Remove that to avoid excess restriction
2) Check the filter screen on the fuel pump and make sure you didn't have a bunch of crud come loose and clog it up.

3) Make sure you installed the gasket between the fuel pump and the crankcase. If you don't get a good seal to the engine you won't have enough vacuum to pulse the pump diaphragm.
4) Perform a thorough carb cleaning with a brand new OEM rebuild kit.
5) Make sure your low and high speed needles are set correctly.


KJ
 
The fuel pump operates mostly with crankcase PRESSURE.------Post the cylinder compression numbers.----Does spark jump a gap of 3/8" on both leads?-----Did you install a new water pump impeller?----Mixing good oil at 50:1 in your tank?
 
kevinj said:
1) No fuel filter is needed between the pump and the carb. Remove that to avoid excess restriction
2) Check the filter screen on the fuel pump and make sure you didn't have a bunch of crud come loose and clog it up.

3) Make sure you installed the gasket between the fuel pump and the crankcase. If you don't get a good seal to the engine you won't have enough vacuum to pulse the pump diaphragm.
4) Perform a thorough carb cleaning with a brand new OEM rebuild kit.
5) Make sure your low and high speed needles are set correctly.


KJ
Click to expand...


hey kevin. Actually remove the filter when i installed new pump and fuel lines, and i used the thick gasket that came with the pump. The screen in the fuel intake in the tank and pump (and even the old pump) are clean, no debris.

It starts, runs and revs up… then dies after a couple minute. You think this necessitates a carb rebuild?
 
Does the bulb on the hose go hard ?----I would say there is an issue with fuel supply.------Operate the manual fuel pump and see if it stays running.-----Or test run with another tank and hose.----Why not post the compression numbers?-----Might mean nothing to you.----But can help folks point you in the right direction !
 
Racer, it goes hard when priming. I dont have a compression tester is the only reason. I did have luck (as it says in original post) with keeping it operating if i pumped while going. Could it be that i added too much oil to the gas? I did have measurer last time i filled it, but i thought i eyed it out well. And i figure even if it was 25 to 1 it should still stay running? I just got new gas but havent mixed and tested yet. Going to try with second tank and new gas tomorrow.

but what else could let it start and run fine for only a minute?
 
A good compression is about $40-----I believe it is running out of fuel.-----I can not see , feel or hear your motor.-----Good luck finding out what is wrong.
 
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