Last summer I was given (I am learning quickly there is no such thing as a free boat) a 16ft john boat with a 1975 Johnson 25hp electric start motor. It had been sitting for about ten years, but ran fine when parked. So I rebuilt the carb and rewired the motor. It fired right up and was running fine (motor in a bucket of water in the yard) Problem was after it was warmed up it would not start again. It has spark, and the plugs are wet, but sometimes it will just not fire up after its warm, even with starting fluid. Any ideas? On another note today I had it running, shut it off, then it wouldn't restart and I went to pull the plugs and one of them stripped the threads. I ordered the helicoil kit for it and am praying that will work. Anyone used these on a spark plug with success? Thanks in advance for your responses.
Need some advice on an Outboard motor problem.
- Thread starter nwjones18
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You're either running out of fuel or spark, or too much fuel.
Pump the fuel bulb much prior to hot restarts. Also, try restarting at different throttle positions.
Replace fuel hoses and make sure there are no kinks.
Make sure that your oil/fuel ratio is correct.
Helicoils work if done correctly. Learn to use a torque wrench on spark plugs.
Pump the fuel bulb much prior to hot restarts. Also, try restarting at different throttle positions.
Replace fuel hoses and make sure there are no kinks.
Make sure that your oil/fuel ratio is correct.
Helicoils work if done correctly. Learn to use a torque wrench on spark plugs.
Put that old Johnson at the front of the boat to use as an anchor... j/k.
If it has the older mag ignition system, you need to get th magnet "recharged" Recharge may not be the correct term but, an older Johnson/Evenrude dealer can zap the magnet to increase the magnetism and you will get a much stronger part. A good spark when turning the motor over by had with the plugs out should produce a spark about 1/2 inch long with some orange/yellow in it. This from experience with the old Green and white series Johnson's.
Kestas
Staff member
FWIW, I once diagnosed a similar condition (no start when warm) to a sheared flywheel key. It put the timing off just enough to allow a cold start but not a warm restart.
Check Ebay, you can probably pick up another head cheap for a motor that old. I never had luck with the helicoils in a head application, especially on a two stroke.
How much oil are you mixing in the oil? I had a fuel pump diaphragm once that was dried out and would pump intermittently, might give that a look.,,
Make sure you're not pulling any air (leaky lines) or that your tank vent is open and working. I've actually COLLAPSED plastic tanks because the vent was closed!
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