On Maui..1973 Buhk diesel....stopped running

unclebraddah

unclebraddah

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On Maui...1973 Buhk DV 20...Recently stopped running. Starts easily enough, gets to full speed and then dies slowly. I replaced all the fuel. I bleed the system and cleaned out the racor. Put a new seal on the lift pump. Im flumoxed and befuddled and I smell like diesel. /forums/images/graemlins/smirk.gif
 
I had a similar problem with my 1978 Hydromarine DM12 a year or so ago. Everything pointed to fuel starvation so bled the system, put new primary filter and fuel lift pump in. Then got engineer to go through it all as nothing seemed to work. Just before he gave up he bled the system for about the 5th time and obviously cleared the problem as it has run sweetly ever since. Bleeding must be more hit and miss than you think so don't give up!
 
Certainly sounds like fuel starvation. And thats one of those things that you have to work through methodically - no one on here can give you an immediate answer. Could be anything from a partially blocked / squashed fuel pipe to an air leak or a tank vent or injection pump.

Start at the tank and work through methodically. First of all, check the flow rate from tank to engine.

Horrible smell isnt it?
 
I replaced all the fuel. I bleed the system and cleaned out the racor. Put a new seal on the lift pump
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What about the primary filter on the engine???
 
Any chance of an air leak into the fuel pipe? I had a similar sort of problem which took ages to find....eventually it was a small split in the fuel pipe running up INSIDE the fuel tank where it met the fitting at the top of the tank. Most boats would have a continuous pipe tank bottom to filter.
When you bleed after a start are you getting air bubbles?
John
 
Sounds like air getting into the system.

Look very closely at the fuel pipes leading to the injectors, especially where go through guides.

I hav'nt had the problem with my Bukh 20, but did with the Bukh 10. The pipe vibrated against the engine block, and gradually wore a tiny hole into the pipe. had to replace several over several years.

Good luck

Mj
 
I agree this sounds very much like an air leak. Difficult (total pain!) to find. Clean everything up, then use a coloured tissue (Tescos coloured toilet paper does fine) to wipe pipework filters etc, carefully after the engine has died again. Any trace of diesel will show up as a distinct darkening of the paper, and if diesel is coming out, air is getting in.

Fine - unless the leak is inside the fuel tank or similarly inaccessible.
 
Have you checked the small filter in the lift pump. I have had it block on me a couple of times and Bukh say it's not carried as a spare, just throw it away as it's not needed. The only time I have had the problem you describe was when running low on fuel in the tank which churned up crud from the bottom.
 
Removed andtook apart the lift pump(ac delco I believe) and cleaned the gauze filter and checked the diaphram and it worked fine. Up to the bowl..fine...to the next pump that splits the pipes into two(one for each cyldner) and that seems to be pumping although the stern side seem a bit weaker. Then blew out the pipes up to the engine intakes,,,and now..i am about to tear out the nozzles. Somebody stop me! Im gonna get some clear tubing and run the lines through that to check for air....still....It starts..begins working its way to operating RPMs(and if I tweak it it will keep running as long as I dont meet operating RPMs, which means burning the dynostarter) and as soon as I do it starts to die.
 
So perhaps the pump after the bowl and filter and before the nozzles..the one that splices the line into two for each cylnder...needs to be adjusted...the spill point...it seems quite a few tools. Anybody have any alternatives for say the sphygmomanometer(blood pressure??)?
 
and perhaps the reason its dying at full rpm is because its not getting enough fuel consistently to maintain those rpms...shims...thos two outlets on that pump(Bryce or Bosch) need shims..any ideas? Mahalo folks!
 
So I put new seals on the fuel pumps. Redid the injectors. Took the cables off the govenor So I could control engine speed and tried to adjust the Stop Magnet. It all started when I replaced the Valve Cover Gasket. I removed it again yesterday to see it split so I cut a new one and put it on with better results and the engine ran longer. Now the engine will run unless I put it under load. And she is bouncing all over the place. Square One. I need to start from the beggining. Im going to adjust the valves. Readjust the Govenor and Stop Magnet. Go through all the pipes. Maybe remove the screen filter in the lift pump.
 
So I put new seals on the fuel pumps. Redid the injectors. Took the cables off the govenor So I could control engine speed and tried to adjust the Stop Magnet. It all started when I replaced the Valve Cover Gasket. I removed it again yesterday to see it split so I cut a new one and put it on with better results and the engine ran longer. Now the engine will run unless I put it under load. And she is bouncing all over the place. Square One. I need to start from the beggining. Im going to adjust the valves. Readjust the Govenor and Stop Magnet. Go through all the pipes. Maybe remove the screen filter in the lift pump. /forums/images/graemlins/confused.gif
 
It all started when I replaced the Valve Cover Gasket.

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Did you use a different thickness joint??????????????

If you did you may have to readjust the decompressor...

Does the engine run if you leave of the valve cover????
 
[ QUOTE ]
It all started when I replaced the Valve Cover Gasket.

*************************************************

Did you use a different thickness joint??????????????

If you did you may have to readjust the decompressor...

Does the engine run if you leave of the valve cover????

[/ QUOTE ]adding to my list
 
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