1963 Johnsons 3 Hp

[green hornett]

Engine Runs For A Few Seconds Then Cuts Out, Let The Engine Sit For A Few Minutes And Then She Will Start And Cut Out.i Replaced Coils And Put In Carb Kit.still The Same Any Takers On What The Problem COULD Be.

 

[tx1961whaler]

Re: 1963 Johnsons 3 Hp

If you're sure the carb float is set correctly, and you've confirmed that the spark is OK, then I would suspect the in-tank filter, shut-off valve, or fuel line. A quick way to check is to disconnect the fuel line at the carb, rotate the line out out a bit, and see if gas flows out of the fuel line with the valve open. Also make sure the gas cap vent is open and functioning.
Good luck, I have a couple of these motors. Once they are tuned up right, they run like a watch for years.

 

[green hornett]

Re: 1963 Johnsons 3 Hp

Could The Head Gasket Cause This Problem

 

[tx1961whaler]

Re: 1963 Johnsons 3 Hp

The first things to check are the spark (using a spark tester), and the compression. Don't be too concerned with the absolute measurement values; what you're looking for is that the measurement is nearly the same between the cylinders.

 

[knight hunter]

Re: 1963 Johnsons 3 Hp

Crankshaft seal ??

 

[F_R]

Re: 1963 Johnsons 3 Hp

Crankshaft seal ??

Doesn't have any. Worn out bearings are possible, but not too likely.

Original questioner: When you were monkeying with the carburetor did you remove and inspect the fixed jet in the bottom of the carburetor bowl? It is deep in the hole behind the hex head drain plug. The jet must be absolutely squeeky CLEAN! Even a trace of anything in it will keep the motor from running.