I have to purchase 16 new fuel injectors for my MEFI 1 502 MPI's. Seeing the price mercruiser wants just about made me loose my lunch! I have spent several months on this board and elsewhere trying to find an EXACT replacement other than Mercruiser. I have had no luck at all....so I guess I am stuck being extorted by Mercruiser. So now the only question is where can I get the best deal on these injectors. The mercruiser part # is 805225A1. Thanks-

Call Witchhunter injector service. They rebuilt mine very reasonable. They may also sell injectors.

I replaced all 16 of mine when building 540 C.I. EFI's. The guys at injector.com (marren fuel injection) treated me very well.

Tim Marren is a great guy!!

You dont need over priced Merc injectors. Contact Marren!!

MJB,

I have a problem with my 2001 Merc 502. It will not start up unless I'm at half throttle. Other than that it runs great. If I were to shut it down and start it right back up, it will fire right up without having to throttle it. But if I wait 15-20 minutes it wont start, I'll have to throttle it again.
Does this sound like I also need injectors?
Are yours acting the same way?

No- that is not the problem I am having. I'm no expert...and there's lots of folks on this board that know better than me but your problem doen not sound like injectors. With fuel injection it could be any number of other issues. Hopefully someone else will comment with some suggestions....but the first thing I would do is hook up a diagnostic tool and see if you get any trouble codes. Thats always a good place to start.

Half throttle on startup actually shuts off your injectors,check your plugs,do a compression test. I have seen exactly what you describe before and it was a blown head gasket that acted like a rich condition. The water was causing some of the plugs not to fire. Good luck.

injector.com or I used a place called www.fiveomotorsport.com for larger ones. I have a used set of the small bodied injectors for sale. Around 150 hrs. on them. Will set set of eight for 300.00

blownboat is correct, there is a 'clear flood mode' between 50 and 75% throttle opening where the ecm shuts off injectors until it it has a tach signal over 300 rpm (run mode).
Could be any of the suggested causes or leaking injector(s).
Any gas smell when she starts?

Actually, most of the mefi programs do a "partial enrich".

Usually 100% throttle = 0% BPW modifier.

If you are having closed throttle start problems, clean the throttle body blade area and don't forget to clean the IAC and it's passage.