2001 Mercruiser 4.3 EFI fuel jet problem

[LWD]

Hello all, hope everyone had a good Memorial Day weekend.

Ours was good for the most part, except.... took the boat out for the first time this year, and it ran very rough with no power. Long story short, I took the flame arrestor off and noticed only one of my fuel jets (port side) was working, the injector on the starboard side was not working. There are two jets total right on top of the TBI. There is a wiring harness that connects to the top of each of the jets. I disconnected the wiring harness' and swapped them, restarted the engine and the problem stays with the injector on the starboard side. I swapped the harness' back to keep them where they were. So, I think this tells me the problem is with the injector itself.

Am I safe in my assumption of the jet being the problem, as opposed to electrical getting to the jet?
Should I still try the 9-volt battery test? Am I safe to try this with the jet still in place, or should it be removed first?

My way of thinking is if replacing one jet, I should probably replace both. It looks like replacing them should be a relatively simple procedure, remove some torx bolts and maybe have a gasket on hand. Or is it not that simple?

Any help and advice on this is greatly appreciated, many thanks in advance.

Also our holiday was partially saved by our jon boat, first time I had kids tubing behind it. They still enjoyed it!

 

[LWD]

I should add, this is a Mercruiser 4.3 Serial Number 0M010426

 

[alldodge]

I would pull both injectors and send them off for cleaning and flow testing by a company that does marine injectors. You don't want an automotive one because they may not test them to 5000 rpm for a period of time. COst is normally around 20 to 25 each.

If one comes back bad then depending on how the other did I would replace the one. There are several on ebay for a set of two fairly cheap. While they may do good work I'm not sure so might have them flow tested before installing

The new part number is 852956A1 and my guess is they can be had at the local GM dealer

 

[LWD]

AllDodge, thank you for the info. I looked up the part number you provided, and they are pricey. But that shouldn't surprise me... Checking with a local GM dealer is a good idea as well. I like your suggestion on sending them off to be cleaned and tested. I'll have to call around tomorrow.

For the last couple years I've had an occasional hesitation when accelerating and thought I had it fixed when I had to have my ignition sensor replaced last year. It didn't fix it, now I'm hoping this was the issue...

Thanks again!

 

[alldodge]

Don't know where your located, but you can find many online

 

[thumpar]

They cross reference to 90's GM injectors. I would find a place that deals with them. A lot of places have it local so you won't have to ship them off. They could also tell you what to cross it to.

 

[LWD]

thumpar, appreciate the tip! I live in Northeast Missouri, Mark Twain Lake, not much around here but we do go into St. Louis frequently. I'll do some checking around and see if we have options there. We have a NAPA store close that also deals in marine cross references.

 

[LWD]

I got the cover off the jets, and a couple of the torx bolts were surprisingly not tight. I guess the jets are just snug and need to be removed with needle nose pliers?

I was a bit surprised to see what appears to be rust on the injectors. I have a water separating fuel filter, and replace it every other year. I attached a picture.

 

[alldodge]

Rust on the parts comes from ethanol fuel. Most injectors have filter baskets and they rust up often on the older boats

 

[LWD]

A followup, I sent my injectors off to the cleaners, neither of them failed during their testing which concerned me, but I got them back and installed and a test run in the carport looks great. Both injectors are working, throttles up good, and the fuel cones are a fine mist, definitely better than before....

Unfortunately when I went to hook up the muffs to start the motor, I noticed a lot of gear oil on the ground coming from a weep hole on the port side, probably a seal...... sigh, if it's not one thing it's another.

Anyway, thank you to all that helped with my injectors, it was greatly appreciated!

 

[Lakeman66]

I got the cover off the jets, and a couple of the torx bolts were surprisingly not tight. I guess the jets are just snug and need to be removed with needle nose pliers?

I was a bit surprised to see what appears to be rust on the injectors. I have a water separating fuel filter, and replace it every other year. I attached a picture.

I am going to try to clean my injectors as well. Any directions on removing them? Thanks!