Anybody know what the spark plugs gap for in a 78 model 100 hp evinrude? thanks

The recommended plug is a Champion L77J4 and the gap is 0.040

thanks badhabit I would truly be lost without nice folks like you.

The recommended plug is a Champion L77J4 and the gap is 0.040

Hello There   I Have 2 Questions...

As an Auxiliary motor on my boat I have a Mariner 4  (on the Lable  Mariner 4M  6EO S 059973 )

I was told that the fuel to use in it was the same as my main motor 50.1   Every now and again I have run the moter for a few seconds and stoped it..  Yesterday my Main motor broke down and I had to use the Auxiliary..   It used what fuel there was in the tank and we ran out of Fuel..  I filled the Tank with fuel from the main motor tank..  The moter would start then die..  Each time it did this...

This morning I notice a lot of Oil down the outside of the shaft coming from a small hole about a foot below the motor..  I now believe that  this motor does not use the 50.1... Maybe just Regular Fuel - But other than the Oil at the bottom how does the motor get lubricated.?   Could you tell me the correct fuel for it please... I have since tried a Mix of 25-1  That stayed going for quite some time then it stoped. It would start and as soon as it is reved up it would stop..

It is the first time in several years that we have had to use it for an Emergency (We were in no Danger but we would have had to get wet:-) )

And do you know the spark plug gap for a For a Johnson 70  Model 70 esl 76b  Using plug  Champion L77CJ4  An old motor but still a goer:-)  I tried the 40 as mentoined as above using plugs (L77J4) and under test at home it runs OK

The main moter I believe the original problem may have been stale fuel  but I had a bit of a fiddle with the Plug Gaps..  They are old moters but the boat is still in good nick.

Many thanks

Norm for New Zealand.

If that engine is 2-stroke NEVER put just straight gas to it. You need to find out what year that engine is and find out what mixture its supposed to take. Since you've had a range of 50:1 and 25:1 and it still doesnt run right, the problem is beyond the fuel. I wouldnt go lower than 25:1.