Engine misfiring, likely suspects list

mtb said:
He could have simply cracked the injectors one at a time to see if fuel was being injected or if it was a fuel fault But then that would cut the cost down
I'd think you have a damaged valve or head gasket problem the compression check will show if it's piston related or valve.
With the injectors out he could test each injector by using a jam jar for saftey to see if there's good spray pattern also correct end of injection and no nozzle leak
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This is my suspicion and if it is the rear cylinder then maybe caused by backflow of sea water into the cylinder when stopping and left there over winter causing corrosion of valve and seat. Quite common where low height engines are fitted when re engining a boat which previously had a higher engine . Often the problem can be fixed by fitting a high level exhaust mixer elbow. I have seen this on Volvo 2030 types and Beta. Beta do a hi level mixer specifically to cope with this problem.
 
Bilgediver said:
This is my suspicion and if it is the rear cylinder then maybe caused by backflow of sea water into the cylinder when stopping and left there over winter causing corrosion of valve and seat. Quite common where low height engines are fitted when re engining a boat which previously had a higher engine . Often the problem can be fixed by fitting a high level exhaust mixer elbow. I have seen this on Volvo 2030 types and Beta. Beta do a hi level mixer specifically to cope with this problem.
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The problem has been discovered in post #75. Nothing to do with valves or seats, I'm afraid. ;)

Richard
 
Tim O said:
Ok!

Its been a while....but we now have a diagnosis.

Apparently, after extensive testing, the problem is with the pump which simply will not deliver fuel properly at number 4 cylinder. They have swapped various bits (valves?) around and what works fine in other cylinder positions wont work in number 4, while the bit from number 4 will work fine in other positions.

Their suspicion is that it may be a hairline crack in the actual pump body/casing which opens up or causes a problem when under load.

The bad news is that it is deemed non-repairable so we are looking at a new pump from Beta Marine at around £715.

Unless anyone else has any bright ideas?

I guess I could hold out and look for a second hand or recon pump....but at the minute I cant basically move my boat off the mooring...which is frustrating to say the least....spring is a coming in!
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I am still wary!
Did the engineer take it to a proper injection pump shop and did they put it on a proper injection pump rig which measures the rate of fuel delivery on each element? If it has been to a proper injection shop they WILL give a definitive answer on what is wrong, no maybe's ! That is why I say I am wary!
Stu
 
skipper_stu said:
I am still wary!
Did the engineer take it to a proper injection pump shop and did they put it on a proper injection pump rig which measures the rate of fuel delivery on each element? If it has been to a proper injection shop they WILL give a definitive answer on what is wrong, no maybe's ! That is why I say I am wary!
Stu
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I know it is easy to sit in the arm chair to fix this prob, one thing bothers me. When the engineer pulled the injectors, why not hang them on the pipe ends and do a field check. Would have saved a bit of money and a lot of faffing.
 
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