Cleaning fuel injectors on 8.1's- should I or shouldn't I?

amajamar

Active Member
Sep 9, 2013
228
Onset, MA
Boat Info
2001 380 Sundancer
Engines
8.1S Horizons
I have a 380 dancer with about 500 hours on 8.1's. They run very well, but I do notice some black exhaust "soot", which accumulates around the above-water exhaust ports. Sometimes at idle they smell like they are running rich, too. Oil testing shows no fuel residue. I'm wondering what other people's experience having injectors cleaned has been. Do you think that this would help the sooty exhaust issue? Do you find that having the injectors cleaned has saved you any fuel? Again, she runs great, so not noticing any performance issues. Looking forward to your thoughts.

Thanks in advance!
 
is your fuel pressure in spec? if no other symptoms, i would treat a couple tanks with techron
 
If it’s running fine and everything else seems fine I wouldn’t do anything.
 
Mine run great as well and they have always accumulated black soot around the top of the large thru-hull exhaust ports. I usually have to give them a quick wipe with cleaner upon returning. I run 4500RPM WOT which is on the low end of the specs, but the engine doesn't seem to lug at any RPM and do most of my cruising at 3600RPM. Maybe too much prop load??

When first started, the engine does have a rich smell, but she runs just fine. I'm from the school of "if it aint broke - don't fix it" so I personally wouldn't be messing with injectors at this point.
 
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I put about 1000 hours on my 8.1s and never did anything to them except run high quality fuel without ethanol in them, change the oil, impellers, the spark plugs and coolant twice. Both turned the same wot RPMs as when brand new when we sold the boat after 15 great years of boating. Use good fuel and oil and follow the maintenance schedule in your owner manual.
 
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Maybe a little, but I learned along time ago not to fix what’s not broke. U said they run fine , no trace of fuel in oil.
Are u idling a lot? Run it and enjoy it.
 
Sounds like good advice, especially if other 8.1's run a little sooty too.
 
When talking to MerCruiser about the engines running rich ( Smell Gas ) they said they make them run rich to cool the pistons with the gas.
 
When talking to MerCruiser about the engines running rich ( Smell Gas ) they said they make them run rich to cool the pistons with the gas.
Well, it's certainly better than running lean and burning a piston, I suppose...
 
I changed them on my last boat with the 8.1. They were 7 years old and 300 hours and I found the manufacturer set for $349 new. Friend had same engine/yr/hours and developed problems with 2 injectors so I went at it proactively. I had the old set tested and rebuilt, and they were not too bad, within ~15% of spec.
I noticed a little smoother idle, but nothing else really changed.
The job isn't that hard, but in hind site I would not have done it based on the minimal improvement, and just waited until I had a problem.

http://clubsearay.com/index.php?thr...injectors-merc-8-1-496-mag.84986/#post-956142
 
Last edited:
I changed them on my last boat with the 8.1. They were 7 years old and 300 hours and I found the manufacturer set for $349 new. Friend had same engine/yr/hours and developed problems with 2 injectors so I went at it proactively. I had the old set tested and rebuilt, and they were not too bad, within ~15% of spec.
I noticed a little smoother idle, but nothing else really changed.
The job isn't that hard, but in hind site I would not have done it based on the minimal improvement, and just waited until I had a problem.

http://clubsearay.com/index.php?thr...injectors-merc-8-1-496-mag.84986/#post-956142
This is good to know. BTW, where did you find OEM injector set for 349? Sounds to good to be true!
 
I did mine with seafoam. Just running the tanks pretty low on fuel the invest in a few bottles, enough to really douse it. Makes them run great and cleans and acts as a preventative as well.
 

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