1992 Trophy not advancing spark

[Metal]

Hey everyone, new here. Just bought a 1992 Trophy with 4.3 mercruiser and alpha 1. The boat only goes 15mph wot at 4200 rpm. When looking at the paper work I got with it, the mechanic that looked at it said he saw the distributor was not advancing. The engine is brand new Jasper, if that means anything. I'm wondering if I replace the module in the distributor seeing how its electronic, in your opinions, would this solve the advancing issue? I'm going to go out tomorrow and try to test it with a volt meter, but looking at it, it looks like it's been in there for a while. Big question with not a lot of info, please take it easy on the newb, Thank you.

 

[Bondo]

Ayuh,.... Welcome Aboard,... Lets find yer answer in the Mercuiser forum,.....

 

[dubs283]

If you post the engine serial number that'll help greatly for those here who have ability to look up info.

What is the current total advance? Is idle timing set to spec?

Guessing based on info provided and that whoever did the long block swap moved all oem merc components to the new it is a thunderbolt ignition. If so, yes replacing the ignition sensor in the distributor would be my first step save a new/different ignition module. Make sure you get an oem, three wire sensor and ground it to the same flywheel stud as the battery ground.

 

[achris]

...The boat only goes 15mph wot at 4200 rpm...

That's not an ignition advance problem, that's a drive ratio/propeller (possibly coupler) type problem. If the ignition wasn't advancing, the engine wouldn't make 4200rpm under load.

Chris.....

 

[Metal]

Completely spaced the numbers, engine: 0d708151, then the tag has transom: 0d655452. When I put the timing light on it I could not see it advance, but it was very difficult to see. The module in the distributor seems to be readily available, but the spark amplifier that bolts to the exhaust elbow not so much.

 

[Rick Stephens]

Pretty easy to check timing advance with an electronic advance timing light. Tough without. You should see something like 26º BTDC advance at 3000 RPM. You can dial in 26 and that puts the flash right on the zero TDC mark. I would do this before assuming anything wrong with ignition system. An advance timing light costs small fraction a Tbolt IV module.

 

[banderberg]

Pretty easy to check timing advance with an electronic advance timing light. Tough without. You should see something like 26º BTDC advance at 3000 RPM. You can dial in 26 and that puts the flash right on the zero TDC mark. I would do this before assuming anything wrong with ignition system. An advance timing light costs small fraction a Tbolt IV module.

Can you check timing advance on muffs? I would think running at 3000 RPM on muffs is a bad idea.

 

[Rick Stephens]

Only need to run that for 3, 4 seconds. Just long enough to see whether the light comes close to the TDC mark.