Trying to dial in my Mercruiser 470.

artificialreef

Chief Petty Officer
Joined
Feb 21, 2009
Messages
504
Hello Folks. Trying to dial in my tired 470. Looks like alot of hours on her but good compression 146 to 150lbs. 1983. Looks like original motor. I had trouble getting it close to the 4 degrees timing and 28 to 32 dwell so bought a new mallory dizzy. The old one seemed to be all over the place. It now sits at 30 degrees dwell and around 5 degrees timing but backfires and pops when i give it throttle. It doesnt when its set at 10 or 12 degrees timing. I rebuilt the carb but it was only my second rebuild. I dont think the choke is working but it still pops after its warmed up. I guess my question is.
Could a carb cause this backfiring when all the specs are correct? I could have botched the rebuild but dont want to go tearing into the carb again for no reason. I get a nice spray when i throttle it. Its a 2 barrel and i also adjusted the screws at the base according to the manual.

Thank you in advance for your gracious responces.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Trying to dial in my Mercruiser 470.

So, what does Mallory recommend for the dwell for their distributor. Merc used two different distributors, one was the Delco with a 28 to 34? dwell, the replacement distributor was the Prestolite and used 39 to 45? dwell.
 

artificialreef

Chief Petty Officer
Joined
Feb 21, 2009
Messages
504
Re: Trying to dial in my Mercruiser 470.

Holy Moly Don, I sure didnt think of that. I only bought the mallory because i couldnt find any other replacements. On this site or anywhere. I would have rather had the direct replacement. I guess some phone calls to cs are in order unless someone else on here had to put a mallory in one of their 470s and knows the dwell setting.
Thank you Oracle.
 
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