3116 ta engine rpm problem

T

Tejo

New Member
Jul 22, 2009
2
San juan, Puerto Rico
Boat Info
40 sundancer 1997
Engines
3116 ta
my engines are having problems with power, my rpm are goin up and down. they go only up to 2,000 rpm.
i change racor filters and engines diessel filters,turbo air filters and add repair kit to racor filters.
they went up to 2800 for a short time. now they are back with the same problem.
after a running for about 15 min. they go up to normal rpm.
need help for this... ?
 
Lots of possibilities here. No smoke? Both engines behaving the same with sync off (wierd)?
My SWAG - I might start looking for an air leak in the fuel lines.
 
The problem is not dirty filters.........once they are blocked, the rpm drops and stays there or gradually decreases even more.

You say engines..........both of them have rpm drops at the same time? or is it one engine.

One possibility for the likely cause is that you have an injector seat leaking on cylinder 5 or 6. When this happens, combustion gasses enter the fuel gallery and essentially turn off the last cylinder. The fix is to ream the injector seat and reseat the injector. This is a job that requires a specialized reamer and some experience to do, so you should call a Caterpillar technician and go from there.
 
Tejo said:
my engines are having problems with power, my rpm are goin up and down. they go only up to 2,000 rpm.
i change racor filters and engines diessel filters,turbo air filters and add repair kit to racor filters.
they went up to 2800 for a short time. now they are back with the same problem.
after a running for about 15 min. they go up to normal rpm.
need help for this... ?
Click to expand...

are knots per hour corresponding with rpm fluctuations..?
 
-thanks for your help.. boaters..
-rpm drops one engine at a time, then port engine does it more than strb engine, first -come one then the other.
-engines temp stay as usual.. cold.
-knots drop down fron 22 or 24 knots at 2500 rpm to 12 or 14 knots when it goes
or drops to 2000 rpm.
-when this happens some little smoke looks around and diessel comsuption is heavier
 
Just for the sake of conversation here: The Webster is most likely spot on.

His port engine is most likely airing up the internal fuel gallery within the head via those pesky injector cup seats. The port looses power, the starboard cant carry the load of the whole boat so she drops to her knees too.

Let the problem child run some with little to no load and the air will be swept clear of the head. The engine will then smooth out until a good load is applied and it all starts again.
 
I appreciate the answer as I am reading everything I can about 3116 and3126 Cats problems. The Admiral wants me to make an offer on a 1994 440 Express Bridge with 3116s and I have heard lots of horror stories. I wish the original poster, Tejo, would tell us how his problem was resolved and at what cost.
 
If injector seats were Tejo's problem, it is a simple $800-1200 repair.

Try searching CSR for 3116/3126 issues and problems. I've posted descriptions of the problems and history more than once. But, generally, if 3116 or 3126 engines pass a mechanical survey, which you would do with any diesel anyway, you have almost no chance of being affected by either of the major issues that plagued Cat owners in the mid 90's.

But Caterpillar engines are like any other diesel.........they won't tolerate being over heated and they don't like being over loaded.

You should thoroughly explore the 44-45EB before making a deposit. There are some design issues that turn many buyers off.
 
Bliss: Don't be afraid of 3100 series MUI (mechanical unitized injection) Cats. Other than the same routine maintenance found with all diesel boat engines, the injector cup seats are no big deal. When refitted and refitted right, they will stay seated long after the engine is warn out.

Many people get quotes for this repair and go for the least expensive. Then there doing it again until a qualified Tech does it right.

As far as cost. This is a 4 hour job per engine with no access limitations. That’s how long it would take me if the engine was on the floor in front of me. Add in a boat, get access to the job, how far down the dock, a service call!

One thing you could do is call the local Cat dealer and ask. Also before you buy, have Cat run the ser#'s for any work done on them.

Good luck with your search.
 
Thank you for your very helpful words re the boat and the engines. I have also been in contact with Randy on Odyssey and he has given some great info.
 
How much space is available above the engine is the critical ingredient here. On the 450DA, there is a lot of working room and this was an 8 hour job to re-seat all the injectors on both engines.

On a 44/45EB, space and access is horrible so it will take more time.
 
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