FunHome

I just bought a 1993 38 Special Baja and it has 502 Mags (Carb.).... Is there anything I should watch out for in these motor's??

The boat shows it has 288 hours and was run in Saltwater so I'm going to change the Exhaust this winter to something better flowing than stock yet still compatable with the silent choice.

Also, I was thinking of taking off the water pumps and putting on a crossover instead. Any other updates or upgrades I should do??

Dennis Moore

For some reason, Mercruiser put a very slow ignition curve into the TB IV 502 carb. distributors. That would be the first place to go to increase performance. A large performance increase will come from switching camshafts to the new GM 502/502 cam and some good exhaust manifolds like the Gil. Install some RV15YC4 Champion spark plugs gapped at .045 inches and a K+N marine flame arrestor.
Good Luck
Sincerely
Dennis Moore

FunHome

What kind of Distributor should I change to? MSD? If so, which one? Do I need to do the whole Kit?

formula31

Leave the ignition alone and especially dont put an MSD distributor on it. And dont bother with the crossover unless you need to get the pump out of the way for a blower. Exhaust, cam, heads, carb, or do yourself a big favor and leave them alone.

JaayTeee

I think the carbed 502's had a
20* advance curve in the module,
while the 454 mag's had a 24*
advance curve module.

On one of my old rigs, I
bumped up the timing 6*,
made a world of difference
on acceleration.

I had no problems with the
TBIV setup, the only thing it
doesn't have compared to
TBV, is a rev limiter,
and " knock control" .

jt

Dennis Moore

You have a fine ignition system. You just need to install a different ignition module that has a faster advance curve. 15248A1 is the Mercruiser part number with 24 degrees advance all in by 3,750 rpm. Set the timing at an idle to 10 degrees advance.
Sincerely
Dennis Moore

Pat McPherson

BUDAH, You crack me up.

So the Crane cam for a Gen V would be?

Hydraulic Flat?
or
Retro Roller?

FunHome

That's kinda what I was thinking.....I've heard that early 500hp's had a problem with Valve Springs and I was wondering if these motor's had the same???

Anything else to watch out for??

epeek

Holy Snikeies! That module is 300 bucks & I would need
2 of them! Does it make enough difference to warrent
the 600 bucks, or do I just bump up the timing. Also,
any detonation problems with 10 degrees advance?
Any help is appreciated! Thanks,Rick.

mcollinstn

Leave your 20 degree module in there and bump to 10. Give it a try and if you are good, then go to 12. It's free.

My 502 carbs like 10 degrees on 87 octane.