salt water in fuel & injector pump

[Mark]

Hi all.

So whats the damage if this occurs?

Topic

[Mark]

thanks for taking time to respond Larry.
So thats what can happen, thats scarey..
Ive got every thing crossed that water did not actually get into pump., But I actually dont know for sure.
Today i gave her a short run without air cleaner on, no apparent change except i did rech 2700 rpm on a prop thats one inch bigger pitch than usual , with or with out air cleaner. that doesnt make sense.
so, air cleaner is fine. I pulled the aftercooler a few hours ago, its not blocked but definitely oily.

[Larry Backman]

Worst case – complete rebuild

This happened to me 3 years ago and it turned into a season ending disaster with a new engine at the end of it.

I took a lot of water into my tanks via a vented fuel cap in a storm and ran home at 8-10 knots for 6 hrs before being able to get up to slow cruise at 17 knots for the last 2 hrs. I knew the engine was hurt at that point as it was burning 10% more fuel at cruise RPM than normal and was not pushing the boat hard.

We got home at midnight that day. The next morning I found my primary fuel filter overwhelmed, my secondary half full of water and a tank with the remainder of the fuel completely emulsified after 8 hours of shake and bake.

I drained the tanks as best we could, filled with new and tried to run it clean which was a bad idea. The engine ran smoky but did hit WOT but was still 10% high at fuel burn at. Cruise.

I had a Cummins mechanic in, he replaced fuel pump and injectors, finding along the way one injector had a broken keeper, and another wasn’t firing, ie I came home on 4 out of 6 injectors.

The engine ran well for the next 60hrs, then developed the same smoke and high fuel burn condition. A boroscope of the 2 holes that had previously failed injectors showed scoring in the cylinder, game over.

Pictures of water in fuel that came out of primary (rear containers) and secondary (front containers) filter as well as post Morten of rusted and scored #4 cylinder. That was the one which blew off the keeper at some point during the storm and wished that piston and cylinder with salt water laden fuel for many hours.

[Mark]

more info

thanks for your concern Philip.

Vessel info is in my signature

Its now on 800 hours

Ive lost 3 to 400 RPM at WOT, which equates to 3 to 4 kts of speed. WOT was always 29kts @ 2900rpm.

I can think of 3 seperate incidents which all occurred about the same time, just before i put her into 5 weeks of dry storage., about a year ago. they may have contributed this problem.

1/ accidental high speed engine shut down (MOB safety device shut the fuel solenoid)
2/ Prop repair after one blade bent by picking up rope during storm
3/ salt water in fuel, picked up in same storm.

so i removed the water from tank and replaced filters and ran the boat several times before the storage. removed bent prop, gave to austral, told them they had 5 weeks to fix it. also gave them all the data sheets from the previous prop repair at ACCUTECK. Got back from OS trip, put repaired prop back on. noticed slight squealing noise from skeg bush in gear at idle, suspect a little bit of nylon rope still in it, local mech and shipwright both said nothing to worry about, it will go away, It did. prop shaft did spin freely when i installed prop.

besides that engine has been operating perfectly, although last trip out i couldn’t get over the hump onto plane after running slow (trolling) for about 1.5 hours. Its never done that before and it scared me.

it slowly started to come good, took a few minutes, turbo started to wind up and then we quickly went up 2200rpm, which as usual, is 22 Kts. thats how she runs,
2000rpm = 20 kts,
2500rpm = 25 kts,
2900rpm = 29kts which is WOT. (but not any more)

The source of the water (tank Vents ) was rectified instantly before the storage, but as both the coarse and fine water seperators had salt water in them, im not sure if it got past the 3rd engine filter and into the injector pump, hence my first post. Its a Tony Re power vessel, the filter setup is his design.

The new filter/seps in order are coarse 30 micron, fine 10 micron then another 10 micron on the engine. 2nd filter now has the WIF probe which ive wired u to the cummins alarm panel. It works, so this cant happen again.

Im working through Tonys Loss Of Power article.
Im not sure if ive got a black smoke problem, cannot see any smoke under way but there is some slight black soot on the transom after a day out, so not sure how this rates in tonys scoring.

things ive checked;
water issue fixed.
hull and prop clean
no extra weight in boat
throttle linkage good
fuel solenoid appears to get full movement but have not removed it totally, no signs of rust.
removed air cleaner, and spun turbo, appears to be spinning free and smooth.
good ventilation into engine box, ran with it open when i checked the WOT throttle linkage
took prop back to Austral 2 days ago, spoke with owner for one hour, he checked prop and said its not perfect two blades out of alignment slightly, buts its not the cause. he said to lose 300 rpm the pitch would have to be out by 2 inches and its not.

I haven’t ran with the air cleaner removed yet, im thinking thats next but not sure if thats a safe thing to do.

[Philip]

With the minimal information you posted, I’ll assume this isn’t a theoretical question and rather something you are currently dealing with.

Your first priority is going to be to figure out HOW the salt water got there and then fix that. Then you need to flush the entire system with lots of fresh fuel and filters to make 110% sure ALL the water is out and never let it get back. Depending on you filtration setup it might be worth a redesign to include water separation and detection.

Water in the fuel pump will cause the fuel pump to quickly fail. It also has the possibility to destroy injectors and ultimately cause the engine to need a rebuild.

How about telling us more so we can help. What symptoms are you having?

Phil

[Author]

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