1978 Evinrude 135 hp misfire

[don aldrich]

1978 Evinrude, sat for 8 yrs, cleaned carbs, new plugs and gas, motor miss fires at idle and some times seems to preignition which causes the engine to dead stop, at top speed you have to baby it to get there. I have also replaced all the fuel lines and squeeze primer bulb. motor seems to start easy, I have since removed the low and high speed jet covers and blew them with compressor, also rebuilt fuel pump, the motor smokes a lot at a 50 to1 mix but i also added some carb cleaner to the gas, it is a 76 135 hp, the fuel take vent is clear, at high speed it will starve for gas and if I choke it it will pick right back up

 

[Will Bark]

Re: 1978 Evinrude 135 hp misfire

Check your flywheel key to see if it is sheared. Others will chime in with more suggestions. Good luck

 

[boobie]

Re: 1978 Evinrude 135 hp misfire

Do a compression and spark test on it. Spark should jump a 7/16" open air gap on a spark tester.

 

[emdsapmgr]

Re: 1978 Evinrude 135 hp misfire

You may want to double-check the year/model. OMC did not make a 135 in 78. Last year was 1976. Possible your carb idle jets may be restricted, causing a lean sneeze. At a low idle it can cause the engine to abruptly shut off.

 

[Fleetwin]

Re: 1978 Evinrude 135 hp misfire

+1 on Lean Sneeze.

That "sneeze" does have a tendency to shear flywheel keys thus messing up timing.

Like others, I'm wondering if you do actually have a 135.

BTW, the 135 never did idle well. That was one of its biggest complaints.

 

[pn]

Re: 1978 Evinrude 135 hp misfire

i'm saying fuel pump. eight years is a long time for a diaphram to sit dry...

 

[emdsapmgr]

Re: 1978 Evinrude 135 hp misfire

Today's ethanol fuels will eat the original fuel pump bladder, so might as well replace that too. If it turns out to be a 78-83 V4, Bombardier makes a rebuild kit for the fuel pump: 393103. Under $ 20

 

[don aldrich]

Re: 1978 Evinrude 135 hp misfire

Check your flywheel key to see if it is sheared. Others will chime in with more suggestions. Good luck

I checked the spark and seems to be good put new plugs in. the bottom 2 were clean,the top 2 had oil deposits, after doing some other work all plugs look the same with signs of oil deposits but running on all 4 just not well.

 

[Bosunsmate]

Re: 1978 Evinrude 135 hp misfire

Check firing with a spark plug tester and also a timing light