can't plane or maybe another issue.

[Bondo]

Re: can't plane or maybe another issue.

To backfire through the carb, either your timing is off (getting spark while intake valves are open = low power), or you have a stuck valve/valves
Only other thing I've seen cause backfiring through carb is severe carbon build up on pistons.

Ayuh,... This is Wrong.... It's only backfiring at WOT... It's going LEAN....
If it were Any of your ideas, it'd do it ALL the time...

The prop may turn slightly in neutral from the oil viscosity...

 

[TJS]

Re: can't plane or maybe another issue.

On a big block? Of course I don't know, but in the auto world if you see that on a stock 454 for any length of time, I think you would see 4600/ 4800 pieces flying off the motor.

Are you speaking from experience or just here-say. Totally not true even on a stock 454.
T.J.

 

[bruceb58]

Re: can't plane or maybe another issue.

deleted

 

[JetBote]

Re: can't plane or maybe another issue.

I don't know where I thought it was a small block. My bad

 

[JetBote]

Re: can't plane or maybe another issue.

And I don't recommend using water, use tranny or power steering fluid.

 

[Familyman1981]

Re: can't plane or maybe another issue.

thank you everyone!!! the timing was off.... well not at start upp just when you start giving it gas what happened was the last owner was working on it and he didn't tighten the distributor bolt so the thing was hoping around while it was running. so i set the timing at 10 because thats my best "guess" where it should be but it wont idle cleanly lower than 1200rpm. so i think i need to advance the timing. i took it to the water today to see how it handled under load and it TOOK OFF LIKE A ROCKET!!!! but topped out at 2200rpm and 40 mph. so im asuming that there is something else not tuned properly??? anyway thanks again and if anyone can tell me where i can get a owners/service manual for a 1981 ski supreme so i can really check what my timing should be set at please let me know.

 

[user64]

Re: can't plane or maybe another issue.

Those rpms for that speed sound wrong. Look on the back of your tachometer and make sure that the switch is set for "8 cyl". Sounds like it might be set wrong or maybe just very inaccurate.

 

[Sharp Shooter]

Re: can't plane or maybe another issue.

thank you everyone!!! the timing was off.... well not at start upp just when you start giving it gas what happened was the last owner was working on it and he didn't tighten the distributor bolt so the thing was hoping around while it was running. so i set the timing at 10 because thats my best "guess" where it should be but it wont idle cleanly lower than 1200rpm. so i think i need to advance the timing. i took it to the water today to see how it handled under load and it TOOK OFF LIKE A ROCKET!!!! but topped out at 2200rpm and 40 mph. so im asuming that there is something else not tuned properly??? anyway thanks again and if anyone can tell me where i can get a owners/service manual for a 1981 ski supreme so i can really check what my timing should be set at please let me know.

Good for you for finding that!!! 2,200 rpms shouldn't equate to 40 mph. Make sure the tach is hooked up correctly.