1977 55 Evinrude

[Adamhcso]

Hello all,
After a long year of working on it, I finally took my boat out on the water for the first time. Everything was going great and then suddenly it throttled down and died. It finally cranked back up and then I could only get about half throttle from then on. I never replaced the spark plugs, so I'm thinking I could have fouled them. What kind of plugs would I put back in there and what would the gap be? Also if anyone has another possible diagnosis, your input would be greatly appreciated. Thanks all in advance!

 

[racerone]

Re: 1977 55 Evinrude

Lots of folks have different ideas on how to go about this.--As far as I am concerned you start with a compression test.--Then check that you have spark on each cylinder.-Real spark is spark that jumps a gap of 7/16" or more.-Did you install a new impeller ? ---If spark and compression are ok then look at fuel / induction issues.

 

[Adamhcso]

Re: 1977 55 Evinrude

Thanks racerone!
Yes I did install a new impeller. That was the last thing I did before I took it to the lake. I will check all that you mentioned and see what I find. Thanks again!

 

[HighTrim]

Re: 1977 55 Evinrude

Agree with above, always step 1 check compression, then spark.

Sounds like a fuel delivery issue from what you described perhaps, but hard to say without going through the paces.

 

[boobie]

Re: 1977 55 Evinrude

Do a cylinder drop test on to see which cylinder is not firing.