Hya

I have a 502 efi (stock) which has been running rougher and rougher lately

I have done almost everything to try and rectify this problem, changed the external fuel filters, pumped the gas tank and refilled it, changed the distributor cap, rotor, plugs, ignition wires

My gut feeling is the fuel injectors need servicing, but am taking it to a repair shop where they will put it on the diagnostic tool, tomorrow.

The tech is already whining about how big a job it is to change /service the injectors and he hasn't even touched the boat yet

So I figured maybe I'll do it myself, but was wondering how difficult the job is, and if I will need any gaskets or kits before I lift the plenum and tear everything apart

A fuel injector service tech quoted $25 an injector to clean and test them, but says they are sealed units. Am I better off getting new ones instead?

Thx

It's not that big of a deal to get
at them, I just did one last week.

Just disconnect the throttle
linkage, the various sensor plugs,
the yellow bypass hoses, remove the
torx head screws on top of the intake,
lift off the upper intake, remove the
4 screws holding the fuel rail to the
intake, the clamp at the end of the intake
that holds the fuel lines in, then the rail
and injectors are ready to come out,
the injectors just press into the rail and
intake.

You will need the injector sealing kits (8)
and the o rings that go on the fuel lines,
and the plenum gaskets.

You didn't say what year the engine is
so I don't want to give you any wrong
part #'s, but the injector we replaced
were $ 112.81, the seal kits were $ 9.93 each
thru mercruiserparts.com

Good luck,
jt

Thanks kindly for your reply

the engine is one of the early ones 1993, I had to go look that one up, it's hard to believe it's 10 years since I installed that motor

10 years... I think I'll swallow and replace the injectors with new ones

I don't really like the idea of doing the same thing twice

I picked up a manual today, so I can educate myself and I have to say after breezing through it the flowchart and voltage testing for reading faults looks a heckuva lot more challenging than doing an injector re and re