HELP lehman 120 died on sudden deceleration
- Thread starter reissue
- Start date
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If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
Xsbank
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We are not talking cars, gasoline engines or Detroit 2 strokes. The risk to filling a muffler is getting sea water in a cylinder causing hydroloc which can bend con rods, serious mechanical damage.
Compressing the fuel in a a Lehman will cause combustion. Period.
Compressing the fuel in a a Lehman will cause combustion. Period.
FF
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There is a big difference between "just chopping the throttle" weather the engine is in gear or not.
Out of gear there should be no problem , however in gear the tranny , shafting and prop may have to be brought back to speed.
This is hundreds of pounds of inertia , so the chopped throttle the gov might not be quick enough to make fuel for the accelerations required to idle.
Out of gear there should be no problem , however in gear the tranny , shafting and prop may have to be brought back to speed.
This is hundreds of pounds of inertia , so the chopped throttle the gov might not be quick enough to make fuel for the accelerations required to idle.
knotheadcharters
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Unloading a diesel engine can trip the overspeed solenoid, check that first.
Ski in NC
Technical Guru
Try that on a diesel powered car and report back.
You will need a shower and change of clothes after your hand is forced off the pipe and soot is blown all over you.
A four stroke diesel develops PLENTY of exhaust pressure to blow water out of the muffler. A full muffler will not cause a no start, but could back flood the engine with water if cranked too long.
cappy208
Guru
@Reissue. Any luck?
Does each engine run off a separate fuel tank? Or is it common? If they each run off different sides can you switch supply tank valves to run both off the side that didn't quit? At least that could eliminate a bad tank pickup or collapsed supply hose.
As others asked, does each engine have an aux inline fuel pump? One of the benefits of the aux fuel pump is it removes air from filter changes. But they also mask failing (ed) fuel lift pumps.
Does each engine run off a separate fuel tank? Or is it common? If they each run off different sides can you switch supply tank valves to run both off the side that didn't quit? At least that could eliminate a bad tank pickup or collapsed supply hose.
As others asked, does each engine have an aux inline fuel pump? One of the benefits of the aux fuel pump is it removes air from filter changes. But they also mask failing (ed) fuel lift pumps.
FF
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The commentb was,"
There is a big difference between "just chopping the throttle" weather the engine is in gear or not.
Out of gear there should be no problem , however in gear the tranny , shafting and prop may have to be brought back to speed.
This is hundreds of pounds of inertia , so the chopped throttle the gov might not be quick enough to make fuel for the accelerations required to idle.
JL "Well you certainly confused me with this. I have no idea what you are trying to say."
When the throttle is chopped quickly the fuel to the engine is almost all shut off..
As the engine approaches idle it needs fuel to operate.
Additional fuel if in gear and the transmission and the rest of the drive train is at a low rpm, as the weight , therefore the inertia of stopped gear will add to the fuel required to idle.
Perhaps the gov was too slow on the uptake , so the engine stopped?
Early in the AM its easy to hear the cool weak engine slow down as it picks up the load of inertia as the engine is put in gear.
The boats with bigger 30-36+ inch props and 3 or 4 inch shafts will notice this the most.
There is a big difference between "just chopping the throttle" weather the engine is in gear or not.
Out of gear there should be no problem , however in gear the tranny , shafting and prop may have to be brought back to speed.
This is hundreds of pounds of inertia , so the chopped throttle the gov might not be quick enough to make fuel for the accelerations required to idle.
JL "Well you certainly confused me with this. I have no idea what you are trying to say."
When the throttle is chopped quickly the fuel to the engine is almost all shut off..
As the engine approaches idle it needs fuel to operate.
Additional fuel if in gear and the transmission and the rest of the drive train is at a low rpm, as the weight , therefore the inertia of stopped gear will add to the fuel required to idle.
Perhaps the gov was too slow on the uptake , so the engine stopped?
Early in the AM its easy to hear the cool weak engine slow down as it picks up the load of inertia as the engine is put in gear.
The boats with bigger 30-36+ inch props and 3 or 4 inch shafts will notice this the most.
jleonard
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Ok FF that makes sense. Thanks for spelling it out
no more exhaust problem
The exhaust is all fine no water all is well so lets remove that from the equation. Mechanic is lookin at the on engine fuel handling ie injector pump, governor, all fuel system checks to fuel filter on engine ok, clean clear fuel and new filters. I like the anchor idea ? ya never know
The exhaust is all fine no water all is well so lets remove that from the equation. Mechanic is lookin at the on engine fuel handling ie injector pump, governor, all fuel system checks to fuel filter on engine ok, clean clear fuel and new filters. I like the anchor idea ? ya never know
cappy208
Guru
Do you have two sets of controls? Upper and lower? Does it do the same from both?
When you start it can you reach down and use the actual fuel lever on the engine and get proper response?
I have seen the morse cables come loose and be erratic. Both the core and the cover must be fastened to work properly.
It makes a difference if you ha e dual stations. If the upper and lower are acting up means it could be the cables all the way down. But if it's just the upper station then it's the cables between the upper and lower. If you can operate the throttle ok right on the engine check cables.
When you start it can you reach down and use the actual fuel lever on the engine and get proper response?
I have seen the morse cables come loose and be erratic. Both the core and the cover must be fastened to work properly.
It makes a difference if you ha e dual stations. If the upper and lower are acting up means it could be the cables all the way down. But if it's just the upper station then it's the cables between the upper and lower. If you can operate the throttle ok right on the engine check cables.
Capt.Bill11
Guru
Beginning to sound like you might have an issue with your injection pump.
thats what we are working on now
Thank everyone for the help, cables pulled checked and re lube. Talked to American Diesel and the next process is checking the hangar in the injection pump to ensure the hangar is moving freely on its track. That hangar follows the action of the throttle cable so it it the next device in line. Again thank ya'll for the suggestions and all will end with a good solution to keep in mind when it happens to someone else.
Thank everyone for the help, cables pulled checked and re lube. Talked to American Diesel and the next process is checking the hangar in the injection pump to ensure the hangar is moving freely on its track. That hangar follows the action of the throttle cable so it it the next device in line. Again thank ya'll for the suggestions and all will end with a good solution to keep in mind when it happens to someone else.
aha moment
The rack inside the injector pump is the culprit. After hours of downstream verification the rack is the last thing in the line. After that is injectors which are ok. Wishing all a very happy turkey day and a full belly. Now finding a mechanic that can do it. I'll post the outcome when it happens. Thanks to all for the help.
Peace
The rack inside the injector pump is the culprit. After hours of downstream verification the rack is the last thing in the line. After that is injectors which are ok. Wishing all a very happy turkey day and a full belly. Now finding a mechanic that can do it. I'll post the outcome when it happens. Thanks to all for the help.
Peace
If that was indeed the problem, could it have been just a coincidental failure, or could it have been caused by the rapid deceleration?
Capt.Bill11
Guru
I once had both injector pumps go bad at the same time on start up on a twin engine 36' GB. I mean what the Hell are the odds of that!? 
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So...there yah go. If something happens with sudden throttle movement, when all fine before, look to the things mechanical that link to said throttle assembly, sounds good logic.
Works for me...
Works for me...
