Port Engine lost some of its power...

[JC]

I need some help/pointers as to where to start looking. HELP PLEASE!!

ENGINE INFO

Engines - Cummins 6BTA5.9-M(250)

Engine #'s 44318961 44566924

ESN 44318961

PROBLEM BACKGROUND

Had Fuel problems. Filters got clogged. Since then have cleaned out the fuel tank and istalled new filters. About half a gallon of "GUNK" came out of the fuel tanks. Pending installation of Multi Stage filtration system and new fuel hoses.

Ran the boat after cleaning fuel tank and filters and putting some new S&B air filters (great filters by the way). Boat gets up on plane with some black smoke but port engine taking 5-10 seconds longer to reach same RPM's as starboard engine. After boat gets up on plane boat runs with minimal amount of smoke (white smoke).

Seems the problems started about a month ago. When going out on a fishing trip the port engine would not get enough power to get the boat up on plane. We had been able to replace only one air filter and the port engine had the old "waterlogged" filter. So I decided to switch air filters from one engien to the other. When running the engine we noticed there was a fuel leak at the high pressure lines going into the injectors on the port engine. We dissasembled and assembled back together untill no fuel leak. Took the boat out again and port engine now getting up on plane.

What I did notice is we started having a loss in RPMs on the port engine when we would hit the backside of a wave. Engine was already taking longer to equal rpms to starboard engine with same throttle setting.

After this incident we had a fuel problem. Filters getting clogged and since then have cleaned out the fuel tank and put new fuel filters.

Specifically the problem is with the same throttle setting the port engine takes longer to reach same RPM setting as starboard engine. THe rpms start creaping up and eventually go above the starboard engine but takes long. Seems I am llosing power. Starboard engine "leads" the por t engine. Starboard engine responds immediately and port engine doesnt. PORT engine doesent have the same amont of power as starboard.

Where do I start looking??

Fuel lines Injectors Injection Pump

Please help me :cry: be happy :D again...

JC

[Sean B]

I'm no expert, but it sounds to me like you may have gummed up your port side engine's injector pump with the cruddy fuel. I've heard of this happening particularly to the BTA's, but I would think any diesel injector pump would be sensitive to gummy fuel. A re-build on that unit is going to be $ painful.

I think I read here about a shadetree-mechanic method to dose the fuel with gumout to attempt to clean the injector pump. You pour a good dose of Gumout (for diesel) into the racor and mix with some of the fuel there, and can also pour some into the secondary spin-on filter. Then run her long enough to get it through the injector pump, during which it will hopefully get cleaned enough to work right.

Only other thing I can think of would be a governor problem, but I would think that would behave/malfunction consistently.

I know there are those on the board with more extertise than me who will chime in on your problem.

[Al C]

I would check the turbo and make sure it spins free might need to be cleaned. If that doesn't help check the aftercooler same story needs to be clean for the engine to breath.

[Mac]

Try draining the fuel filter then filling the fuel filter with Sea Foam and running it, it safetly works very well at cleaning out deposits in the fuel system.
You could also get a boost guage and try it on both motors to compare boost levels a specific RPMs.

[JC]

Thanks for the tips. Keep them comming please. THe more info the better decision I can make.

I was suggested by a mechanic that the mechanical fuel pump (lift pump) could need a replacement and not providing adequate fuel pressure. Might be.

Would like to hear some opinions on where to start. I was thinking change injectors first and see what happens.

Opinions??

Thanks,

JC

[In Memory of Vicroy]

I've followed your posts over on boatdiesel. I have the same engines in the same B31. Loss of power as you describe without belching a lot of smoke is an indicator of a fuel delivery problem vs. an air delivery problem. My experience has been that if the fuel restriction is on the suction side of the fuel lift pump, the symtom is a varying of rpm vs. if the restriction is on the pressure side of the lift pump, its just a reduction in power and rpm with no varying. Yours sounds like a restriction on the pressure side of the lift pump, which even includes a weak lift pump. Most common culprit is a clogged spin on engine fuel filter or weak lift pump. I clogged an injector pump once and the symtom was hard starting but it seemed to run OK once lit. I'd change the spin on, making sure you fill it full with clean diesel, test, then swap the lift pumps if you don't have a spare to try. Tear into the injector pump as a last resort. If you are getting any, I mean any, variation in rpms, trace back the suction side all the way to the tank pickup, check every hose fitting for suction leaks, the o-rings on the Racors, the shut off valves, etc.

UV

[JC]

Thanks Vic. Wow!! I just read your numbers on another post. 24.5 knots at 2400 RPM's. Nice. I can only do 20-21 knots at 2400 RPM's. Do you have a full tower?? Whats max RPM's on your boat??

Thanks for all your valuable info.

JC

PD. I see you raising a sail on your avitar. Nice. Maybee one day you will want to come catch a few here in El Salvador.

[In Memory of Vicroy]

That's one of the 169 sails the UVI group caught at Tropic Star in Panama week before last. A hoot. I know your boat since I helped Andre when he was buying her. I live in Baton Rouge.

Yep, 24.5 kts at 2400, a half tower with full enclosure, big genset, not a light boat. She will hit 2650 WOT. Hope to get her back from Katrina repairs next week.

Work on the pressure side of the lift pump and the lift pump itself. Since you have had the injector lines open, just for sport bleed them with the engine at idle - crack the nuts and make sure all the air is out of the lines. 6B's are famous for air locking.

UV

[Andre' B]

Hey UV;

Thanks for your continued help!! It's good to know good people. This site sure has a bunch of them.

Andre'