AQ131B backfires in the water at 3000 RPM

"I recently installed a pertro

"I recently installed a pertronix ignition kit, timed the engine 6 degrees BTDC with a timing gun. Engine runs awesome in the yard on the trailer and does not backfire at all. When i put it in the water and throttle forward, it wants to backfire and sound like it will stall sometimes once i reach close to 3000 RPMs. Out of water it runs great like there is no load on the prop or something.

any suggestions on what i can check?"

Check that the advance mechani

Check that the advance mechanism in the dist is working properly.

"Two things I would try:

1&

"Two things I would try:

1) The 6ºBTDC setting is for regular gasoline. If you are using mid-grade or higher octane, you may want to try 10ºBTDC.

2) Make sure that the ignition timing is 32º-36ºBTDC at 4400 RPM.

3) Make sure the accelerator pump is working (i.e. it is squirting fuel into the carb during acceleration) and the stroke is set correctly. This picture is from a car carb accelerator pump and your accelerator pump does not have a pin (it should have an adjusting nut), but will give you an idea.



4) Make sure the ignition leads go to the correct spark plugs. The firing order is 1-3-4-2, clockwise in the distributor cap."