4.3l lx help . runs slow

[Rick Stephens]

Nope,..... Marine distributors don't have vacuum tubes,....... Donno what ya got there,.....

There are many distributor caps that are vented when a base gasket is used. The vent turns a 90degree angle to prevent a spark from being able to escape.

 

[Sprintracing82]

Update . i changed the coil. Old was corroded and green. Coil Plug was also green and distributor points. Cleaned those. Old coil more then likely not a right coil for boat.
I got boat out for a few minutes over the weekend. Throttle response is so much better. Just seems to run better not sluggish. I think 19p 14.25" prop isnt right. Now got 4600rpm at 35mph and was still rising but I let off.
So now got the motor issue fixed , for the most part. What would be a better prop size or pitch. ? Would like to get 40s mph. Also Speedo might be off. Never gps checked yet. Might go back to 21p? The 19p seems good for the little bit of tubing I pulled. But seems rpm was going to high.

 

[Rick Stephens]

Update . i changed the coil. Old was corroded and green. Coil Plug was also green and distributor points. Cleaned those. Old coil more then likely not a right coil for boat.
I got boat out for a few minutes over the weekend. Throttle response is so much better. Just seems to run better not sluggish. I think 19p 14.25" prop isnt right. Now got 4600rpm at 35mph and was still rising but I let off.
So now got the motor issue fixed , for the most part. What would be a better prop size or pitch. ? Would like to get 40s mph. Also Speedo might be off. Never gps checked yet. Might go back to 21p? The 19p seems good for the little bit of tubing I pulled. But seems rpm was going to high.

The right pitch is the prop that gives you the correct Wide Open Throttle RPM. You cannot target a speed. If you want more speed than a boat can give you you need more motor.

That said, there probably is no reason your boat should not run in the forties. But prop it for WOT with a quality prop designed for best speed and you may not like its performance when pulling tubers or wakeboards.

 

[Sprintracing82]

I understand top speed and tuning would need different things. But engine still had more to go with 19p. Engine was still pulking at 4600 rpm and I didnt want to go over a certain rpm. So would a 21p lower rpm by 200rpm and give slightly better speed . at 4600 rpm ??

 

[Rick Stephens]

I understand top speed and tuning would need different things. But engine still had more to go with 19p. Engine was still pulking at 4600 rpm and I didnt want to go over a certain rpm. So would a 21p lower rpm by 200rpm and give slightly better speed . at 4600 rpm ??

21 pitch will lower RPM approx 200 RPM, maybe a bit more.

 

[Bondo]

I understand top speed and tuning would need different things. But engine still had more to go with 19p. Engine was still pulking at 4600 rpm and I didnt want to go over a certain rpm. So would a 21p lower rpm by 200rpm and give slightly better speed . at 4600 rpm ??

Ayuh,..... Maybe, or not,..... If it's still makin' power enough, yes,.....

That motor with a 4bbl. carb is rated at 4800 rpms,...... 5 grand won't hurt it, but the 2bbl. carb runs outa breath,....