Originally Posted by articfriends

Maggetti marelli fiat injectors on the 98 to 2001 454/502 mags arent the greatest for matching, even new from mercruiser, a east coast guy sent me 8 new injectors he paid the big dollar for from mercruiser, 1 flowed 8 to 10% lower than 6 that were close, 1 outflowed the rest by 16 to 20%, he ended up getting two more from a place in fla or georgia that flowed really close to the 6 good ones for about 90$ a piece instead of the 150 or 160 each he paid for from mercruiser. Brian orlandi had same problem, he was flowing, testing and installing 16 new ones on a boat that had some kind of insurance claim, he ended up using 5 or 6 old ones to get 16 that matched fwiw. I always thought mercruiser tuned stock 502s pig rich out of laziness and retuned them much cleaner but now im convinced they do it because they were avoiding warranty claims from injectors flowing low, especially over time as they get older and fouled up. I have done about 15 sets of 454/502 mag gen 6/mefi3 injectors now since buying my machine last year and have seen mismstched flow in almost every set. About half of them came to.me after guys melted a cylinder, i would never run a 15 or 20 year old efi motor in something i owned without pulling injectors and checking/cleaning themnon a machine, cost so little compared to a meltdown, Smitty

Originally Posted by johnny b good

I have been concerned about my injectors since I have been reading more about this topic. I have twin 1997 502mpi mags with a touch over a 1000 hours on them. The engines are stock original and have had nothing done to them other than normal maintenance. They run great and I have noticed no deterioration in performance or any more oil consumption since I bought the boat in 2006 with 230 hours. I have talked to a few local Merc. Mechanics and they didn’t seem to concerned or try to push me to have my injectors professionally cleaned and flowed. Based on what I read I can’t believe they wouldn’t push injector cleaning service harder on me. I see your in Michigan too. Do you perform injector cleaning and flow testing for others besides yourself or know of a good local place for it? I live in Macomb County.
Thanks.

Originally Posted by F-2 Speedy

Yes he does, another to consider is the O-rings on the top and bottom of the injector, deterioration over over 20 years of heat from the engine,

Originally Posted by johnny b good

I have been concerned about my injectors since I have been reading more about this topic. I have twin 1997 502mpi mags with a touch over a 1000 hours on them. The engines are stock original and have had nothing done to them other than normal maintenance. They run great and I have noticed no deterioration in performance or any more oil consumption since I bought the boat in 2006 with 230 hours. I have talked to a few local Merc. Mechanics and they didn’t seem to concerned or try to push me to have my injectors professionally cleaned and flowed. Based on what I read I can’t believe they wouldn’t push injector cleaning service harder on me. I see your in Michigan too. Do you perform injector cleaning and flow testing for others besides yourself or know of a good local place for it? I live in Macomb County.
Thanks.