New Engine No Power

  • Thread starter Thread starter KAM
  • Start date Start date
No problem engine-wise running without exhaust, but ensure the seawater doesn't come back in the disconnected exhaust! Remember to arrange something to catch the cooling water discharge, either a bucket or a gash hose over the side. The exhaust gases will be hot!
The usual problem with old exhaust hose is the two layers its made of delaminate internally so the external surface looks ok, but the inside has been peeled off, flattened and bunched up by the exhaust gas, giving more and more back pressure to the engine the faster it tries to run. Try and straighten it out and look down the bore with a torch, both ends disconnected, or disconnect at the engine, and run a waterhose through it, but this is not so reliable a test if you have a watertrap or it exits under the waterline. Let us know what you find.
 
I can't see any way that the exhaust could possibly be the problem, as the engine will apparently rev freely when out of gear. The volume of exhaust gas at a given engine speed is exactly the same whether the engine's in or out of gear.
 
I checked the saildrive is free when out of gear. It also seems to spin over quite freely in gear on the starter. The props looking less likely as the culprit. Lack of fuel does seem to be the most likely problem. I did suspect the lift pump but disconnected it and just ran the engine fron the fuel in the filter bowl which did not make any difference. I am beginning to think there is some sort of restriction or fault in the injection pump/stop valve area.
 
I'll check all that out tomorrow. Thanks for all the advice everyone. I'll let you know what I find.
 
exhaust gas volume will increase as more fuel is injected into the engine under load, which burns to produce CO2, and.....
 
Exhaust looks OK. I was wondering if it could be something as simple as the position of the throttle arm stop. Not sure if it just controls a fuel valve and the speed governor is seperate or if the arm controls the governor. Would it be possible for the arm stop to be wrongly adjusted so that it achieves full revs off load but can not supply the extra fuel to get full revs on load. Beta say the only check full revs as they do not have a dynamometer.
 
the last resort- look in the book!
IF you have a BD1005 (28HP), then one of the options in the owners manual for low power is a "Governor spring incorrectly mounted - dealer to adjust "(page 18), and your symptoms are consistent with this possibility. I have fitted several Beta engines, but have never had to open up the governor, so do not know what exactly you may find. At work I might have a workshop manual, I will check tomorrow.
Looking through this download from Beta, I see that there is also a mechanical stop lever at the governor, probably with adjusting screws, but if their position is locked with paint I would be reluctant to start fiddling as there may be warranty issues. Beta may not load test their engines, but possibly Kubota do at the factory? Anyway they both have an excellent reputation.
Do you still have the original propeller? A couple of other forumites have suggested refitting the old, or replacing the prop, and this would be my next move as well. Its a folding prop, and if it was assembled incorrectly it may be giving too much pitch at revs- a very small machining error in the hub can result in relatively big pitch error at the blades.
You'll get there eventually!
 
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