Re: Test prop 1978 johnson 75hp stinger
You are certainly welcome to search for the test wheel in question. Test wheels are expensive, which is why they are not readily available in the used market.
Few shops will have all the wheels needed for the vast array of motors that are worked on. I won't get into how rarely they get used...
Few also realize, you need a reasonable size test tank for them to work properly. They move water and any air that gets sucked in will ventilate the wheel.
That said. You do not use a test wheel to do a link and sync... 1 problem solved.
For that motor the "Joe Reeve's timing method" will work well. No water needed, never mind a test wheel. Just cranking speed...Problem 2 solved.
Fwiw - It is very common for the timing to be spot on after a rebuild, if the components were not disturbed.
If it helps you sleeps nights, you can confirm the timing on the water with a helper driving. Obviously, pick a calm day!
(Timing At Cranking Speed 4?)
(J. Reeves)
NOTE: If your engine has the "Fast Start" feature", you must disconnect/eliminate that feature in order to use the following method. The "Fast Start" automatically advances the spark electronically when the engine first starts, dropping it to normal when the engine reaches a certain temperature.
The full spark advance can be adjusted without have the engine running at near full throttle as follows.
To set the timing on that engine, have the s/plugs out, and have the throttle at full, set that timer base under the flywheel tight against the rubber stop on the end of the full spark timer advance stop screw (wire it against that stop if necessary).
Rig a spark tester and have the gap set to 7/16". Hook up the timing light to the #1 plug wire. Crank the engine over and set the spark advance to 4? less than what the engine calls for.
I don't know the full spark advance setting your engine calls for, but to pick a figure, say your engine calls for 28?, set the timing at 24?. The reasoning for the 4? difference is that when the engine is actually running, due to the nature of the solid state ignition componets, the engine gains the extra 4?.
If you set the engine to its true setting at cranking speed, when running it will advance beyond its limit by 4? which will set up pre-ignition causing guaranteed piston damage! You don't want that to take place.
No need to be concerned about the idle timing as that will take care of itself. The main concern is the full advance setting.
Be sure to use your own engines spark advance settings, not the one I picked out of the air here in my notes."
