Re: 1984 Chrysler 125 - at what revs is max advance?
Chrysler outboard engines are similar to cars but if you want to dynamic time them, you have no choice but to do it at higher speeds.
The linkage is designed so full timing comes at about 3/4 throttle. This is cruise position and corresponds to about 1/4 opening of the carb butterflies. It varies a bit from engine to engine. RPM will also vary depending upon hull, prop, and load so there is no set RPM. Further advance of the throttle--depending upon whether or not you have older Motorola ignition or Newer Prestolite ignition may retard timing a degree or two. The carbs open wide, the engine makes a lot more noise and uses a lot more fuel, and top speed is only 2-5 MPH more.
However, no matter which ignition system you have, it is not necessary to time with the engine running. Either can be time in the driveway, although I always check my results on the water.
Timing for Chrysler can be as far advanced as 32 deg. BTDC if you use land based pump gas. However, late Chryslers were recommended to be timed at 30 BTDC as were Force engines.
If you have distributor Motorola ignition. all you need to do to time it is remove the top plug. turn on the key, put the control handle in full forward, and slowly turn over the flywheel by hand. Watch where the plug sparks in relation to the flywheel marks. Just be certain there is no gas in the engine or remove and ground the other plugs. Some of these engines when in good condition WILL kick, even when turned slowly by hand.
If you have Prestolite distributor ignition, remove all the plugs put the control in full forward, and with the key on, jump the solenoid to crank it. Use a timing light to see the flywheel marks. I forget, but I think static timing is 28 deg BTDC at cranking which will automatically advance to 30 BTDC while running. (has to do with slop in the linkage and the flywheel magnets)
In either case, the prop will be engaged so don't get your legs near it.
