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1981 35hp johnson seahorse

B

Bonez

New member
Last week I was out running the engine in full throttle and the engine would throttle down on its own and die out. It sounded like it wasn't getting any fuel. This happened a few more times on that trip. When I got home checked all the fuel lines, put some sea foam in the fuel and checked the spark plugs. I pulled the cable off one plug and it would run fine, and when I did to the other one it would barley run at all. Could it be a coil shot? I was also thinking the fuel pump might be bad also. I had it out 2 more times after I messed around with it and it ran good. The last time it ran good until on the way home it started to die down again. Once it got to the boat launch I had a hard time starting it to get it on the trailer. My first thought is that the coil or fuel pump has has something to do with it. I’m no expert thanks for any information.
 
Re: 1981 35 johnson seahorse

Not a good idea to run the engine if there's a problem..... it just gets worse.

Check comprssion, check spark. Let us know what you find.
 
Re: 1981 35 johnson seahorse

Compression gauges are pretty cheap, available at Wal*Mart, K-Mart, automotive part type stores, etc. They come as screw in types and (most common) ones that have a rubber tip. Have all spark plugs removed, stick the gauge in the plug hole and crank the engine over..... 3 or four revolutions will do it.

Checking spark..... Spark plugs still removed. Set up a tester with a 7/16" gap. The spark should jump that gap with a strong blue lightning like flame.... a real SNAP!

No tester? Build this one.........

(Spark Tester - Home Made)
(J. Reeves)

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.
Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:
　
..........X1..........X2
.................X..(grd)
..........X3..........X4

Let us know what you find.
 
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