1970 60hp Evinrude Bogging

[rayodunne]

Had the boat out last night for first time this season and motor will go from idle to wot no problem then after 20 secs revs drop to about 3800 and I back the throttle off and everything is fine engine idles fine also. Then if I want to I can go to wot again and repeat the process.
When I got home I discovered a leak in fuel line on carb side of fuel pump. I found this by squeezing the bulb on fuel line and holding it tight. So I fixed that and came on here to read up on any other possibilities. I was going to pull the high speed jets tonight and clean them. Any other items I should look at?

 

[DJ]

Re: 1970 60hp Evinrude Bogging

I think you found your problem.

 

[rayodunne]

Re: 1970 60hp Evinrude Bogging

Thanks for your quick response. Would a small leak on that hose be enough to cause the bogging on it's own? I have no idea how much it was leaking at wot as I had the hood on at the time.
I'll still pull the jets and check them for peace of mind as I have to drag the boat 25kms for a test run.

 

[F_R]

Re: 1970 60hp Evinrude Bogging

A leak on the carburetor side would make a mess and absolutely be a fire hazard, but unless it is a gusher, wouldn't cause the problem.

Are you running L77JC4 or QL77JC4 spark plugs? If you aren't, you should be.

 

[rayodunne]

Re: 1970 60hp Evinrude Bogging

I am running with a new set of QL77JC4 just put in after seafoam decarb. Decarb helped alot with idle as it now idles smooth.

 

[rayodunne]

Re: 1970 60hp Evinrude Bogging

Pulled the carbs and they were absolutely spotless. High speed jets are clean also. Checked carb linkage as I reassembled everything and it is all good. I am ordering all new hoses for carbs today and a new 'T' connector. What size hose should go from the fuel pump to the middle carb? Anything else I should be looking at?