Loss of power under load

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camkorn

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Hi,

We have a vetus 13hp engine on our westerly pageant. Last summer it developed a loss of power under load around 1000rpm. There is no unusual smoke and the engine runs smoothly. We took the heat exchange housing off and found a clog of black soot where it joins the elbow. Because of corrosion we ended up replacing the housing anyway. Hopeful that this would fix the issue but alas it did not. We have just replaced the fuel filters and this also hasn't fixed the problem. Thinking of the injectors now but would like any advice on other possible causes.

The prop seems to turn freely when out the water and also the shaft.
 
camkorn said:
Hi,

We have a vetus 13hp engine on our westerly pageant. Last summer it developed a loss of power under load around 1000rpm. There is no unusual smoke and the engine runs smoothly. We took the heat exchange housing off and found a clog of black soot where it joins the elbow. Because of corrosion we ended up replacing the housing anyway. Hopeful that this would fix the issue but alas it did not. We have just replaced the fuel filters and this also hasn't fixed the problem. Thinking of the injectors now but would like any advice on other possible causes.
The prop seems to turn freely when out the water and also the shaft.
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Lack of power under load is also caused by lack of fuel, check the pick up pipe in the tank and also make sure no partial blockages to the lift pump.
 
skipper_stu said:
Lack of power under load is also caused by lack of fuel, check the pick up pipe in the tank and also make sure no partial blockages to the lift pump.
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And check the exhaust system hoses perhaps for partial blockage due to declamation and collapse internally ??


delamination! ................. stupid spellchecker
 
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Thank you, you have both given me something to try. I think our tank may be gravity fed with a tap - I have not had a really close look at it can't remember for sure. I will have a close look and check the pipes.
 
And check fuel pump is delivering the full amount at high speed. Not unheard of for the pump to fail slowly with leaking valves.
 
When we had that it is was fuel leaking from a joint. Stop the engine put kitchen roll around every joint, lift pump and any filter that has a removable bowl at bottom then run the engine at 1,000rpm and wait until the engine looses power diesel in the kitchen roll will be obvious.
 
Well we have run the engine with the fuel cap off to see if there was a blocked vent and there was no increase of power. The exhaust system is clear. We have taken the injectors off and took them to be checked and they are fine - the chap said they are not the cause of our problem - we haven't put them back on yet but it's not sounding hopeful! The fuel lines all look clear and there are no leaks along the whole system that we could identify. :-(
 
>LOL When air is drawn in, the engine coughs, splutters, and dies.

It depends on the amount of air if it is not much, which is normal, the then revs go down fairly slowly for a few minutes then engine cuts out. That was our experience.
 
Hi,

Just thought I would come back to let you all know that the end problem was the propellor being bent - even though we have no recollection of ever having hit anything.
 
KellysEye said:
When we had that it is was fuel leaking from a joint. Stop the engine put kitchen roll around every joint, lift pump and any filter that has a removable bowl at bottom then run the engine at 1,000rpm and wait until the engine looses power diesel in the kitchen roll will be obvious.
Click to expand...

Blue paper hand towel is even better.
 
camkorn said:
Hi,

Just thought I would come back to let you all know that the end problem was the propellor being bent - even though we have no recollection of ever having hit anything.
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I was just going to suggest this when I read your post. If the engine runs entirely normally when out of gear (granted, this may be hard to tell), then the problem will lie in the transmission or stern gear. Slipping gearbox; shaft misalignment or bend; a wrap around the shaft; or as in your case, a damaged prop.
 
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Loss of power cane caused by a mcroscopic hole that lets air in and fuel out, put kitchen roll around the bleed screw all fuel line connection and fuel filters, run the engine for 5 minutes and see if there is any diesel in the kitchen roll. Our boat came with copperr pipes andt that happened often so I replaced it with normal fuel pipe.
 
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