Home › Forum › Ask A Member › Johnson Seahorse TN28 Timing off? › Re: Johnson Seahorse TN28 Timing off?
Mike, It does not sound as though the problem here is the sparkplugs other than an improper gap setting as MarvK stated. You mentioned that you have NGK plugs now. The correct NGK model is the B6S gapped at 0.030".
I read that you have spark on both top and bottom cylinders. How did you test for spark? Did you check it with a neon spark tester or check to see if the spark would jump a 1/4" air gap as FrankR mentioned. With all new ignition components installed correctly you should have a very strong spark. If the spark is not strong, then you should really focus on the ignition components and installation. Clean, properly set points are very important as Steve A W stated.
The primer on these motors is also very important, and if it is not working properly, the motor will be nearly impossible to start cold. When you depress the primer five or six times, does fuel come out of the rotary valve intake on the front of the motor? If no fuel, then that is something to look at. Also, after priming and pulling the motor over a handful of times, if it does not run, then take a look at the sparkplugs. They should be wet with fuel.
Have you done a compression test? That is a good indicator of the internal condition of the motor and is also a good way to check for a blown head gasket. If the compression is good, then there is no reason why this motor can’t be made to run. It’s just a matter of eliminating/ruling out problems one at a time.
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