BMC 1.5 fires but cuts out

[Sweeny Todd]

 

Asking for my brothers boat which has a 1.5 BMC in it. It fires up and runs for around 5-10 seconds and then cuts out. So far we have checked the deisel ( had it cleaned due to water in the tank), the fuel pump, injectors etc. I'm now running out of ideas and would appreciate any suggestions. Thanks for reading.

[SLC]

Can you immediately restart it once it cuts out?

We have a Betamarine engine which would fire and then stop running. Next day it would start up again, run and then pack up. A crack was found in the priming pump casing - i.e. an air leak. So, look for an air leak. Might not be your answer but this can cause frustrating problems.

[Sweeny Todd]

Hi. Thanks for your suggestion. Yes I can restart it immediately after it cuts out. I'll check everything again to check for a leak.

 

[David Mack]

Air leak on the fuel system was my first thought too. So most likely on the suction side of the lift pump i. e. between the fuel tank and the lift pump.

[Tony Brooks]

Not really enough info but:

 

Is this  a new boat for him? Previous history is very important.

 

How much fuel is in the tank? Six inches may well be out of fuel.

 

Does it have a water trap/filter between the fuel tank and filter? If so, what make and model or a photo? The ones that would be common on 1.5 powered boats have a number of O rings and it is all too easy to get them wrong, twisted etc, allowing air to be drawn in. If it has a filter or strainer, have you cleaned/renewed it?

 

Have you checked the strainer under the lift pump cap (on no account take the rubber seal out of the cap). This is often forgotten and if you had water in the tank it may be full of water and muck.

 

All comments about the water trap apply to the engine filter, I note that you say nothing about changing the filters.

 

Did the engine rev up on its own just before it stopped?

 

Are you absolutely sure that you have properly bled both the low and high pressure fuel systems.

 

Photo of the injector side (from the top is fine) of the engine to ensure it is properly piped up.

 

 

 

 

 

[Bee]

Mine did this for a while and still occasionally does it, I found that if I bled the thing right through it would start, run, cough a bit then die, If I removed the filter it was not full, there was a good 1/2 inch of air in it and therefore it must have been sucking air, I have gone through every inch of pipework and remade every joint and it still sometimes does it. These things can be really infuriating. I sometimes think a day tank above the engine is the last resort.

[Tracy D'arth]

1 hour ago, Bee said:

Mine did this for a while and still occasionally does it, I found that if I bled the thing right through it would start, run, cough a bit then die, If I removed the filter it was not full, there was a good 1/2 inch of air in it and therefore it must have been sucking air, I have gone through every inch of pipework and remade every joint and it still sometimes does it. These things can be really infuriating. I sometimes think a day tank above the engine is the last resort.

I have occasionally had a crack in the top of the dip tube in the tank allow air into the pipework. The test is to brim fill the tank, if it then doesn't get air in you have found the problem. What you can do to fix it is another matter!

[Tony Brooks]

Like wise, depending upon what the dip tube is made from, the tube can split or rust through.

 

I am wondering in Bee's case if opening the small hole in the return banjo bolt in the filter head to (say) 1mm would help. In fact, I wonder if his is blocked so it is not passing sufficient fuel/air back to the tank.

[Bee]

Thanks, I'll have a look at the horrible thing next time I'm on the boat. Stupid air leaks.