Engine won't rev

black mercury said:
The return line from the injectors should go to the filter head, and a pipe from it back to the tank. There should be a banjo bolt there with a small hole in it to take excess fuel back to the tank. I believe in a previous post you said this was a bolt with no hole in it. It shouldn't be. Check this out, or take bolt to the diesel shop where they should have the proper bolt.
Click to expand...

Glory be! You're right. The spare engine's filter housing does indeed have a banjo bolt with a bore to the interior. I'll swap them over with high expectation that it will work. That solution will solve another. I have two tanks and, although there may be an advantage in being able to route the return to either tank, it will be automatic if rigged as you suggest.
 
Looks like you may have solved it now but here is a photo of my BMC 2.2 engine, which presumably is fairly similar in layout. Overspill fuel from the injectors is piped back to the filter housing and a second banjo bolt takes overflow from there back to the tank.
 
vyv_cox said:
Looks like you may have solved it now but here is a photo of my BMC 2.2 engine, which presumably is fairly similar in layout. Overspill fuel from the injectors is piped back to the filter housing and a second banjo bolt takes overflow from there back to the tank.
Click to expand...

That's what my filter housing looks like but it seems the missing hole was the culprit. Can't see inside your banjo bolt!
 
With light winds yesterday p.m., we drove up and down our stretch of the canal. Maximum speed by log was 4.5 knots. That's twice the previous "record" but still pretty disappointing.

The engine revs were still below 1000. I believe maximum diesel torque starts around 1500. Perhaps we need to get above that "hump" to use the proper output of the engine. The stiffness in the prop shaft I believe is from the cutlass bering. That should ease once we enter the very fine grinding paste otherwise know as the Bristol Channel.

I examined the end of the blind bolt in the filter housing. It had a film of rust pitting. Bang in the centre was the suggestion of a hole. Inside, there was a 3-4 mm diameter drilling. The smallest drill I have is Ø0.6mm. It will not enter.

The hull speed should be between 5 and 6 so not far off.
 
Reading this with interest..
Despite the assorted red herrings. It shouted loudly 'lack of fuel' since there was no black smoke from overfueling, along with the low revs in neutral. I was surprised that the diesel service guys did not point this out.
Try using a needle to clear the bleed hole, as they can be quite small. But I am still a bit puzzled how that can have such an effect.

Two days ago we went out to try a couple of systems on a boat with a 1GM10, found it very sluggish and was concerned, as the short steep chop and fresh wind were effectively stopping the boat. Went back and had a look. Changed the fuel filter and it completely envigorated the donk.
 
Graham_Wright said:
I had a look under the boat yesterday afternoon (forgot the wetsuit but wasn't really cold!).

There were just a few strands of weed and the prop turned easily. The lack of leverage in the boat probably was the cause of the previous apparent stiffness.

The gland is a Deep Sea Seals one, i.e. ceramic disc to bronze, no tightening required.

Suspicion (don't really understand enough for more than that) now centres on the injector pump. This was recently professionally rebuilt. The engine doesn't emit clouds of smoke or struggle. It just seems happy with the revs it achieves. I don't understand how the governor works but that could be the cause (as someone has suggested). I have a spare pump and may swap them over. The access is abysmal.

Tomorrow expert friend has promised to attend and I will report back.
Click to expand...
 
I
Graham_Wright said:
I had a look under the boat yesterday afternoon (forgot the wetsuit but wasn't really cold!).

There were just a few strands of weed and the prop turned easily. The lack of leverage in the boat probably was the cause of the previous apparent stiffness.

The gland is a Deep Sea Seals one, i.e. ceramic disc to bronze, no tightening required.

Suspicion (don't really understand enough for more than that) now centres on the injector pump. This was recently professionally rebuilt. The engine doesn't emit clouds of smoke or struggle. It just seems happy with the revs it achieves. I don't understand how the governor works but that could be the cause (as someone has suggested). I have a spare pump and may swap them over. The access is abysmal.

Tomorrow expert friend has promised to attend and I will report back.
Click to expand...

Check fuel supply from tank to main fuel filter not blocking supply to engine. Problem may be there.
 
"Expert friend" did not turn up (again!).

Bleed from the injector pump is now connected to the spare filter input connection (as before) and the bolt securing banjo connector has been drilled through (sewing needle modified). The output from the banjo is now significant whereas before it could be ignored (just the injector spillage). Interestingly, the banjo output also contains bubbles and the air trap that follows the filter is clear. I guess the air in the filter (still to be traced) rises to the top of the housing and is blown out by the injector pump output.

I am still unhappy with the speed and now suspect the prop may be oversize. The various available on-line calculators suggest a prop diameter of 16.8 inches and pitch of 9.4. I have a spare prop which is 17 X 7. There is no mention in the calculation formula of blade form. The spare one is conventional and symmetrical. The one fitted is roughly the same dimension but the blades are quite a lot bigger in area and asymmetrical,
 
It sounds like you may have the fuel system incorrectly configured. You seem to infer that the mechanical lift pump and electric pump are in parallel however it is more usual to have these pumps in line with each other with the electric pump nearest the fuel tank and then pumping to the mechanical lift pump. so the fuel flows through both pumps in the same line. If your return line goes back to the filter then make sure that there is no way this is also finding its way direct to the the tank via some other line as this could cause a loss of fuel boost pressure. You should either have the spill return direct to the tank or back to the engine filter inlet via a throttling nipple as on many Volvos but not both. Have you got the right lines connected to the correct fittings on the prefilter?
 
The thread is becoming long (!) but #24 explains. The tanks are in the keels and the electric pump lifts to the first filter, thence to the engine lift pump and then to the on-engine filter.

The bolt through the banjo on top of the filter was the culprit as on the Volvo you reference.
 
If your prop was holding the revs down there should have been some black smoke , so I think you are still not getting full fuel out of the injector pump.The bmc 1.5 as a marine engine had a continuous rating of 30hp @3000 revs, so to get anywhere under motor the prop must allow the engine to get up to 3000rpm so your existing prop (props) seem on the big side 15 X 10 or even 14 X 10 would be suitable assuming 2-1 reduction.
Are you getting up to 4000rpm no load yet ?
Jim
 
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