1999 502 mag starting and reving issues!!!!
 

I have a 1999 Baja 33 Outlaw with 502 Mags - 350 hrs. My port engine and port manifold leaked water into cylinder 5 resulting in 75 lbs compression in that cylinder. I had both heads redone and replaced the all exhaust manifolds with Eddie Marine exhausts (very nice!). Compression is 150 lbs in each cylinder with new spark plugs.

I now can't run over about 3,200.....and it started and ran perfect before the work (but 500 rpm behind the starboard engine at WOT).
It's also hard to start, with a weak idle and I did put in a new IAC, that made no differnce. I have been dealing with this since Memorial Day!

Anybody have any Ideas?? I have a scan tool, so timing reads good with no codes!! Could the distributor "Control Module" be bad....or maybe the "Coil" going out? How about that "Knock Sensor", that can slow it down. The rev limit works just reving it up to 5,000 (at the dock) ECU bad?? UGH!!

Please help me!!!

(I'm going to swich parts with the other engine this weekend-->Scary)

Could be the alignment... maybe the installer didn't do it right (or do it at all)

ummmm.........no.

We did the alignment, on both. I bought The Mercruiser "Alignment Tool"
from Bam Marine, and both were perfect.....could slide the tool in and out
with just two fingers! The time spent to get it close was about half an hour. Took almost 3 more hours on each engine to make it perfect.
Every time we tightened all the bolts....it would change. Make no mistake, that's a tough job!!

gaurdian mode maybe??

dist cap position
 

Had a friend that had the same problem last year after replacing a long block 350 mag, turns out the dist cap was in the v6 position??? anybody else ever hear of this.....it's worth a shot, symptoms were the same

The scan tool only shows you what it thinks the timing is, it assumes the base timing is set correctly. I would start by rechecking the timing (in base timing mode).

Dave