1968 3hp Evinrude lightwin

[alanR1]

I got a new fuel pump and it immediately fixed my fuel flow problem. New issues however have arrived. At WOT it will only idle. It will stay running with no problem but it will not accelerate.. You can hear it pulsing a bit, like it wants to go faster but won't. We noticed that the bottom plug is fouling out almost immediately but the top plug looks good. We checked compression and it seemed low, about 32 psi per cylinder. Is that too low. We tookk of the carb and checked the float and the jets, all look good. Any suggestions. We adjusted the low speed knob and the lean/rich knob and nothing really happened at all.

 

[OBJ]

Re: 1968 3hp Evinrude lightwin

Alan...take a look at spark. A cold spark will cause your problem. The 32psi/cylinder sounds low to me but have seen them run well at these low psi's, just as long as they are within 10% of each other. Try a decarb which may bring the compression up.<br /><br />Test the spark across a 7/16" gap. Should fire across the gap easily. If not, trouble shoot the ignition system.<br /><br />Keep us posted.

 

[alanR1]

Re: 1968 3hp Evinrude lightwin

I took the plugs out and grounded each one and checked spark and it looks strong on each plug. I will try a de-carb but can I do it with the rpm's as low as they are, like I said before it won't go past idle. What do you think could cause this?? I re-checked the carb inside and out and it seems perfect. Only thing to think about is that gas is coming out of the front of the carb like it is flooded sometimes, but the float is not stuck. I am stuck, with few options. This motor was given to me and haden't been run in probably over 10-15 years.

 

[Paul Moir]

Re: 1968 3hp Evinrude lightwin

Retest with OBJ's 7/16" gap. At mid throttle up, your ignition system may be arcing over up in the flywheel area. If it can jump 7/16", it's not likely there's a problem. <br />Getting it to jump a .030" gap at atmospheric pressure is pretty well meaningless on these engines.<br />Good luck!

 

[Chinewalker]

Re: 1968 3hp Evinrude lightwin

That motor will not run at all at 32psi. Try a different gauge.<br /><br />I would definitely be looking at ignition for the source of your problem...<br /><br />- Scott

 

[OBJ]

Re: 1968 3hp Evinrude lightwin

When you checked the carbs Alan, what float did you see? Was it a cork float or a black plastic looking float? If it's cork, definetly time for a carb overhaul. The cork is probably had the shellac coating eatin' off and is "waterlogged"...which means it don't float no more.

 

[DJ]

Re: 1968 3hp Evinrude lightwin

Ditto OBJ. If the float is cork, get it out.

 

[alanR1]

Re: 1968 3hp Evinrude lightwin

I will look into the ignition. As for the carb, it does have the cork float but the schlak coating looks good and we put it in a glass of water and it floated. Did I mention the gas is periodically coming out of the front of the carb? ????