1978 Johnson 115 Ignition Timing

[Kreegan]

I recently purchased a 17 ' boat with a 1978 Johnson 115 V4. Compression is good ~125 psi (+-3psi) for all cylinders. I rebuilt the carburetors & fuel pump after finding that the wot speed of boat was about 9 mph. Butterflies open all the way with advanced throttle. Sync appears good, at least as best I could follow the manual. I suspect ignition timing is not advanced or (advancing enough). I have a timing light . I believe the previous owner may have pulled off the flywheel. When I put a dial indicator into cylinder one and rotate flywheel to indicate TDC on that piston the TDC marking on the flywheel is about 2 inches away from pointer. 1) Is it possible to install the flywheel and have it indexed this far off ? 2) Can I create new timing marks and attempt to time engine off of those or would it make more sense to try to pull flywheel and reinstall correctly ? Or am I barking up the wrong tree ? Any guidance would be greatly appreciated ..Thanks

 

[emdsapmgr]

Re: 1978 Johnson 115 Ignition Timing

Your compression is solid. I'd pull the flywheel for a sheared key first. That will absolutely make the timing off if the flywheel is not located properly on the keyway. If you don't torque the flywheel nut to the right torque, the key can easily shear when the starter impacts the flywheel. It needs to be 100-105 lbs. The next thing to do is set the timing pointer. The factory manual tells how to adjust the timer pointer for TDC. Once you have this set correctly you do not need to change any timing marks on the flywheel. Once you know that TDC is dead on, re-run the engine and check re-check the timing. Also, check the spark advance rod which connects the timer base to the spark advance lever. Make sure the rod is connected and that the timer base moves with the spark lever. Post your findings.

 

[Kreegan]

Re: 1978 Johnson 115 Ignition Timing

I pulled the flywheel and found a new looking stator which is good, the bad is that the key is sheared in half. Do you have any suggestions for removal , can it be carefully ground out or is this a machining operation only ? Thanks again .

 

[Kreegan]

Re: 1978 Johnson 115 Ignition Timing

Ok ..I was able to use a small punch and hammer it out..

 

[emdsapmgr]

Re: 1978 Johnson 115 Ignition Timing

You will need a factory key to replace the old one. Ask your Bombardier dealer for a 307480. Around $4. You might get a spare, just in case.