Question about paint chips in fuel system

[stouchton]

My boat is a 2004, so I have dealt with this - basically changed fuel regulator (3x) and fuel cell. But wouldn't this also effect the injectors?? I do not know much about my injectors, besides being over 20 years old. The engines are 4.3GXI-E. I do not know if these injectors have screens, or if paint chips could simply get to the nozzle/valve.

If paint chips can gather in the injectors, can they be cleaned?? Or should they just be replaced?

I am planning on pulling the injectors this winter and having them tested. I do not have any real issues, just down a little on power (3800rpm max instead of 4200/4400). When I had way too much fuel pressure I had no issues with power. Now that fuel pressure is corrected (55psi idle, 50psi 2000 rpm no load) got me thinking I may not be getting proper fuel delivery.

Pulling the injectors might be a difficult project - clearance is nil.

I appreciate any thoughts.

 

[Scott Danforth]

do a compression check.

yes injectors can be cleaned

if you can get the spark arrestor off, you can get the injectors off.

 

[stouchton]

do a compression check.

yes injectors can be cleaned

if you can get the spark arrestor off, you can get the injectors off.

Thank you

I can get the arrestor off, so should be good to go.

Good idea on compression check. Changed the plugs yesterday but forgot my compression gauge, but simple enough now that I finally found a decent spark plug socket that fits under my GLM manifolds.

 

[cyclops222]

EFI engines can ruin engines with lightly blocked injectors. They start to run some cylinders smoothly LEAN.

 

[ESGWheel]

Please read this thread (link) explains a lot....

 

[BRICH1260]

Prop pitch can play into engine not getting to full RPM`s. Might consider looking there before tearing into engine.

 

[Scott Danforth]

but simple enough now that I finally found a decent spark plug socket that fits under my GLM manifolds.

standard socket with OD turned down.

 

[stouchton]

standard socket with OD turned down.

I have a perfectly good Atlas in the basement and never even thought of that. Got hyper-focused on finding a socket that would work!

 

[Lou C]

Did the manufacturer really stick the engines under an un-movable hatch?
If so, this is why some people will never have another inboard or I/O. But, if you can get to it, go for it!

 

[stouchton]

Please read this thread (link) explains a lot....

Great link. Left me with a question that might be a misunderstanding. How do the paint chips get past the screen on the high pressure pump? Is it simply too coarse to stop them?

 

[stouchton]

Prop pitch can play into engine not getting to full RPM`s. Might consider looking there before tearing into engine.

Props have been the same for 20+ years, so I don't think that is the culprit. They are pristine and not damaged.

 

[stouchton]

do a compression check.

yes injectors can be cleaned

if you can get the spark arrestor off, you can get the injectors off.

I did perform the compression check - 160 to 165 PSI on all cylinders.

I am planning on removing injectors this off season.

 

[stouchton]

Did the manufacturer really stick the engines under an un-movable hatch?
If so, this is why some people will never have another inboard or I/O. But, if you can get to it, go for it!

Yes they did. I called Monterey to inquire about access, and they suggested to cut the deck. Fortunately I am only 5' 8" and 160lbs so I can squish into some tight spaces. At age 61 the body does not like it.....

 

[stouchton]

EFI engines can ruin engines with lightly blocked injectors. They start to run some cylinders smoothly LEAN.

Good point - I did limit running once I got fuel pressure under control.

 

[airshot]

Once you get things cleaned up and running, consider adding more fuel filters or figure out where the chips are coming from. I always add and extra filter of two when I get another boat. My moto is you can't have to.many..

 

[airshot]

Did the manufacturer really stick the engines under an un-movable hatch?
If so, this is why some people will never have another inboard or I/O. But, if you can get to it, go for it!

When ever I looked at boats with I/O's, first thing I consider is access for service. I do my own, so easy access is primary. Walked away from some really nice boats because of poor acess...

 

[ESGWheel]

Great link. Left me with a question that might be a misunderstanding. How do the paint chips get past the screen on the high pressure pump? Is it simply too coarse to stop them?

I can say that the screen on my regulator was contaminated with fine black specs, so it does get past. And when I had my injectors cleaned, the report was “very dirty”.

 

[stouchton]

Just wanted to say thanks for all your help. Managed to get the fuel rail off before wrapping the boat up for the winter. The only difficult thing was getting the injectors out - they were the originals and well painted in!

I bought my self an early Christmas gift, and tested the injectors as is first. At idle speeds, all seemed well. But at medium to high speeds it became evident that one injector could not flow. And, of course, the inlet screen was clogged with paint chips. So I learned that the finest screen in the fuel system is on the inlet of each injector.

So ultrasonic cleaning and replacement of screens allowed them all to flow within 2% of each other.

I will have to wait till next spring to truly test out, but I feel this easily explains how it would start and idle fine but would limit horsepower at full speed - basically running on 5 cylinders instead of 6.

 

[Lou C]

Just thinking of the difference in fuel flow from idle to 4500 rpm in terms of GPH makes you realize the effect of fuel restrictions..

 

[dingbat]

So I learned that the finest screen in the fuel system is on the inlet of each injector.

Shouldn’t be if your using a 10 micron filter per the manual