140 evinrude ignition or carb problem?

[basspirate]

i have a 1978 evinrude 140. when the engine is cold its very hard to start. once warm it starts easily. when i go out i can only get it up to about 3000 rpms. if push the choke in for a sec at the 3000 rpms it picks up about 200 more rpm's but then goes back to 3000. i've rebuilt the carbs, checked the coils, tested spark at idle and all cylinders are fireing. the compression on all cylinders is between 125 and 130. any ideas as to why i cant get wot?

 

[tashasdaddy]

Re: 140 evinrude ignition or carb problem?

did you remove the high speed jets?

Ethanol and fuel lines
replace all fuel line with Alcohol resistant lines. Ethanol deteriorates, the rubber lines, then they start to sluff off on the inside, going directly to the carbs. Settling to the bottom of the bowl. Contaminating the carbs high speed jets. clean a rebuild carbs, flushing fuel line before connecting to carbs.

 

[ezeke]

Re: 140 evinrude ignition or carb problem?

If the chokes are 100% closed and the warm-up arm is raised fully, the engine should start rather easily. This is because the fully choked carburetors enrich the fuel mix which is required for a cold start and raising the warm-up lever advances the timing.

To check the chokes, take the air cover off and watch the choke plates as someone cranks the engine while pushing in the ignition key. The plates must move together and stay 100% closed while cranking.

http://forums.iboats.com/showthread.php?t=323642

 

[ezeke]

Re: 140 evinrude ignition or carb problem?

If using the choke on the running engine increases RPM, you are running lean.

If re-checking the carburetors does not help, look carefully for any air leaks including all of the hoses, filter, and gaskets. And, be sure that the gasket between the fuel pump and the engine is air-tight. Also check the fuel pump membrane.

 

[basspirate]

Re: 140 evinrude ignition or carb problem?

i removed the high speed jets and the choke does stay fully closed. i'm gonna try rebuilding the fuel pump although i didnt see any tears the membrane did look a little stretched. does anyone think this could be a ignition problem or does the fact that chokeing it raises the rpm's above 3000 cancel out the ignition idea?