QuestionHello, I was wondering if there is a way advance the timing on a 14hp Tecumseh model # HH140-160001? It is off of an h14 Bolens if that helps-not sure if it will help. The reason I want to do this is because I would like to run a very high octane fuel in the engine.
Thanks, Richard
AnswerThe two things to do are increment the flywheel forwards and tighten the ignition coil up to the flywheel magnet. Use a dollar bill to gap the coil to the flywheel and that will give you a little bit of advance. For Briggs and Honda engines, you can get offset flywheel keys in different increments to advance the timing. Since Tecumseh closed down, I don't know how available performance keys are, but people are still racing them.
If you can't find offset keys, then you can just take the key out and advance the flywheel by fractions of an inch until you start to see detonation and then back off a little. The key doesn't actually hold the flywheel in place, it's just a reference. The taper of the shaft and flywheel are what actually holds the flywheel in place with the retaining nut holding things down.
You should increase the compression to get the real benefits of higher octane. You can try head gaskets of varying thicknesses, I've made them out of copper sheeting before. Do a clay test to check for valve clearance just to be on the safe side. Porting the intake and porting and polishing the exhaust would also reap some real benefits as would using a better muffler like a SuperTrapp. You can make a head pipe and then paint a white strip down it. Run the engine for a few minutes and where the paint discoloration stops, cut the pipe and install your muffler there. You will have to play with it to find the optimum length for your set-up, but that's a good starting point.
Then there are all sorts of other mods internally to lighten up the rotating assembly and stuff like billet flywheels and whatnot. But doing the basics will help realize the performance potential of higher octane.
