Perkins 108

[marinerowner]

My perkins 108 has to be primed if I don't used it for 3 days or longer. It runs great but I think there is a fuel system leak after the fuel pump.( Just replaced lift pump to try to correct this issue). The engine tends to smoke a lot on the initial start up. I have checked everywere for leaks and haven't located any. Maybe fuel injector stuck open? Any thoughts would be greatly appreciated.

[zeehag]

check your banjo fittings, filter system, lift pump, and check injectors--- i added a small inexpensive assist pump and havent a problem anymore-- had a leak at the lift pump.
what color smoke is she making for you to see.....hoiw often do you use her......smoke can be from many things.....

[Chief Engineer]

Sounds like you have a air leak on the suction side.....Check your primary filter and see if it full of fuel...check all connections from fuel pump suction side to tank......One of the biggest culprits is the o-ring or "olive" (as our brothers across the pond call it) on the inlet side of the pump is in good shape and not cut

[marinerowner]

The smoke is mostly a blue. Just installed new lift pump. I'm leaning towards injectors next. I spent a lot of time looking for leaks and tightening lines ect. It takes 2-3 days for the fuel to get air in it. After that amount of time it starts then runs for 2-3 second til air reaches injectors. Thanks

[zeehag]

blue is oil burning. check your compression. might be a different problem than your fuel one. 2-3 days is what a friend had when banjo fittings for racor filters were bad.

[Cheechako]

By primed do you mean squirting in the intake, bleeding the injectors, or lift pump priming...?you could have an injector stuck open... depending on how good you are at reading oil color... it's wierd, I had trouble getting my 4-108 not to start, open injection lines etc, the damn thing could not be cranked without running!

[sdowney717]

the damn thing could not be cranked without running!

if a diesel is a serious oil pumper then it can ingest its own engine oil and run till it seizes. one way to stop that is cut off all air or oxygen.

Diesel engine runaway - Wikipedia, the free encyclopedia
look at this guy trying to hold this diesel while it runs away

http://www.youtube.com/watch?v=WrAeU...yer_detailpage

[Chief Engineer]

Originally Posted by marinerowner

The smoke is mostly a blue. Just installed new lift pump. I'm leaning towards injectors next. I spent a lot of time looking for leaks and tightening lines ect. It takes 2-3 days for the fuel to get air in it. After that amount of time it starts then runs for 2-3 second til air reaches injectors. Thanks

When you prime...you are on the low pressure side of the Injection Pump

Any leak past the injection pump is on the High Pressure Side. Leaks there are very apparent

Don't waste your time futzing with the injectors.

Leaks on the suction side are air leaks in....not fuel leaks out.

Air gets in....fuel goes back to primary filter or tank.

[James S]

Welcome to the forum Daniel.

[roberttigar]

Check the raco unit. When mine did this, I discovered a hairline crack in the bowl that was just enough of a leak in the system to cause it to loose pressure. Bob

[marinerowner]

By priming I mean taking out the lower bleed bolt completly for the injector pump then we crank the motor for 5-10 seconds. then the motor starts. Then we put the bleed bolt back in and it runs great until we let it sit a couple days. We use this boat at least once a week. Thanks for all the input.

[Rocketman]

I am having a simular problem and maybe someone out there can help me, I also have a perkins 108, and it used to start istantly, now if it sits a couple of days it will start but after cranking 15 seconds or so. I replaced both fuel filters on the boat and the problem started after replacing the filters. The filter on the engine is a fram P8043 and came with 2 rubber o rings, a large one that is obvious goes to seal the filter and a small one that I could not determine were it went. I looked at the old one that I took off but it did not have seem to use the smaller one. Any thought would be helpful

[marinerowner]

On mine there is an o ring at the bottom of filter and 1 at the top. People often don't get them lined up and it will cause system to draw air. I have heard that there is an after market replacement that will allow you to screw the filter in much like an oil filter.

[Chief Engineer]

Originally Posted by marinerowner

By priming I mean taking out the lower bleed bolt completly for the injector pump then we crank the motor for 5-10 seconds. then the motor starts. Then we put the bleed bolt back in and it runs great until we let it sit a couple days. We use this boat at least once a week. Thanks for all the input.

I don't believe that is the proper way to bleed a Perkins.

Why don't you use the PRIMING/LIFT PUMP.?

Doing it your way with cranking the engine....introduces air into the injection pump.

[marinerowner]

Thanks Chief, I guess I failed to mention that step but I do use the lift pump first but its hard to get all the air out that way for some reason. I also have a new electric pump in between the fuel tank and Racor filter/ separator.One other thing to mention is that the electric pump slows down after a few moments but never really stops completely. I would think it would completely stop once system is pressurized. Also, the electric pump doesn't seem to be strong enough to pump fuel to the injector pump.