85 S&S - sudden loss of power

[thatsmrmastercraft]

You would only need a ballast resistor if you change back to points or a coil without a resistor.
I changed to an insulated post and have all my points parts in a box in the garage.


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[thatsmrmastercraft]

Forgot to mention to set your timing to 10° BTDC.


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Rebuilding Holley Carbs $289
Rebuilt complete Holley Carbs $425

[Tmac in Folsom]

great; thank you...I've also read here that it's desirable to set the timing on the water, in-gear, at idle (5 mph lock-in)......do you concur? Then again; it's always possible that I misread the other timing post?

[EricB]

10 deg BTDC at 600 rpm. In gear if you want, in water out of gear, does not matter as long as it's close to 600 rpm. It's mechanical advance so rpms are more important than any other parameter.

[Tmac in Folsom]

thanks Eric.....so, I need to adjust the carb idle screw to attain 600 RPM first? Then se the timing?

[EricB]

Yes. That will work.

[thatsmrmastercraft]

Set your idle speed to 600 RPMs in gear 675-700 RPMs in neutral.


Custom wheel and tire packages
Rebuilding Holley Carbs $289
Rebuilt complete Holley Carbs $425

[Tmac in Folsom]

Question: my original Pleasurecraft manual says to set timing at 6 deg BTDC; why are you guys recommending 10 deg BTDC?

Would it change the timing at all because I've replaced my old Prestolite "points" distributor with the new PerTronix Billet disti?

[d2jp]

Originally Posted by Tmac in Folsom

Question: my original Pleasurecraft manual says to set timing at 6 deg BTDC; why are you guys recommending 10 deg BTDC?

Would it change the timing at all because I've replaced my old Prestolite "points" distributor with the new PerTronix Billet disti?

According to the good folks at SKIDIM:
"1986 - prior for a 351 PCM should be set at 6 degrees BTC @600 RPM. PCM 351's 1987 and later should be set at 10 degrees BTC."

I would go with what your manual says, assuming it's the correct manual for your year engine. It doesn't hurt to try anything between 6 and 10 degrees - and you should be able to find the sweet spot somewhere in there. After setting it, disconnect your throttle cable and increase your RPMs a touch, you should see the timing mark advance.

[Tmac in Folsom]

thank you Jack....I've got it set at a hair over 6 deg TDC right now and am anxious to get her out on the water and further fine tune if necessary. And yes; my PMC is the correct manual as I'm the original owner and have all the original paperwork including my $17,800 receipt from 1985...