mrsaundep
Seaman
- Joined
- Jun 9, 2009
- Messages
- 55
MCM 140, Serial number, 5568367, Alpha 1
(Further to my previous post July 30th 2012 01:35pm, where I installed a new Delco EST distributor kit as the previous distr bushes were worn. I also rebuilt the carb with a repair kit as it was full of crud, Installed new fuel/water separator, new filter in the Carter lift pump, and cleaned the small filter in the carb inlet.
After the above the engine starts nicely and runs o.k. Goes ahead and astern o.k, and back to neutral o.k, the idle speed is steady about 750rpm, and returns to 750 after each shift in/out of gear. I had her running ahead at 1000rpm (still roped to the quay) for about 10 minutes, all seemed o.k.
Went out on the river, after running about 1200rpm for around 20 minutes, with the odd burst at 2000rpm (there are speed limits on the river here), she suddenly stopped and would not start. Would crank but no fire.
I cracked open the fuel line going into the carb and cranked the engine, it was dry, no fuel. Cracked open the fuel pipe outlet from the Carter lift pump (low volume type), also dry. Removed the pipe completely, cranked the engine several times and eventually got fuel spurting out in bursts as the Carter pump strokes. Tightened the fuel pipe to the lift pump discharge, cranked a few turns until I got fuel at the pipe fitting into the carb, tightened that fitting, cranked and she fired o.k.
Again she ran for about 15 minutes at 1200rpm, then same problem. Engine stops and will not start. I have to ?bleed? the fuel pipe between lift pump and carb as described above to get it going each time. And so the cycle goes on.
I suppose it is sucking air in somewhere between tank and Carter fuel lift pump, but damned if I can find it. The entire pipe line from tank suction to lift pump is only about 6? long, but some of it near the tank is difficult to access.
I will describe the fuel suction system and what I have checked thus far;
- copper pipe fitted inside the tank, vertically, from tank bottom to a fitting on the top of the tank, pipe has a fine mesh strainer on it ? checked the pipe and strainer are clear,
- copper pipe from fitting on the top of the tank into a ? turn fuel shut off valve, - checked, no holes in pipe, fittings are tight,
- Fuel shut off valve - checked, valve shuts and opens o.k, no holes in pipe, fittings are tight,
- copper pipe from fuel shut off valve to filter/water separator - pipe o.k fittings tight,
- Filter/water separator cartridge Quicksilver 35-802893Q01, - fittings are tight, new filter installed and filled up, filter is tight, I have tried to remove the filter base to check it for cracks but the mounting bolts are rusted up and I will need to cut them to get it off. Inlet and outlet pipes are connected the right way round!
- Rubber hose into Carter fuel lift pump - tight no holes,
- Fuel lift pump, Carter low volume type - I have removed this, stuck the suction hose into a 5l tank of fuel and stroked the pump by hand (it is tight but will pump), it soon delivers fuel with each stroke, a good spray each stroke. With the engine running I took the small clear plastic hose that goes between the base of the Carter pump and the carb, there is no fuel spraying out of this (so I think this means the Carter pump diaphragm is o.k), there is a slight suck/blow from this hose at the carb end, but it is dry, no fuel. Filter in the pump is clean and the gasket is new,
I have taken off each piece of pipe and blown through it with air, all are clear.
I really am at a loss as to what to check next. I know the entire pipe line is clear and tight when I pressure it, so I think I might need to try and put a vacuum on the pipe line to see if it is sucking air in, but I am not sure how to do this?
Any advice / help on what to do next or if anyone has experienced anything similar, would be MOST welcome!
(Further to my previous post July 30th 2012 01:35pm, where I installed a new Delco EST distributor kit as the previous distr bushes were worn. I also rebuilt the carb with a repair kit as it was full of crud, Installed new fuel/water separator, new filter in the Carter lift pump, and cleaned the small filter in the carb inlet.
After the above the engine starts nicely and runs o.k. Goes ahead and astern o.k, and back to neutral o.k, the idle speed is steady about 750rpm, and returns to 750 after each shift in/out of gear. I had her running ahead at 1000rpm (still roped to the quay) for about 10 minutes, all seemed o.k.
Went out on the river, after running about 1200rpm for around 20 minutes, with the odd burst at 2000rpm (there are speed limits on the river here), she suddenly stopped and would not start. Would crank but no fire.
I cracked open the fuel line going into the carb and cranked the engine, it was dry, no fuel. Cracked open the fuel pipe outlet from the Carter lift pump (low volume type), also dry. Removed the pipe completely, cranked the engine several times and eventually got fuel spurting out in bursts as the Carter pump strokes. Tightened the fuel pipe to the lift pump discharge, cranked a few turns until I got fuel at the pipe fitting into the carb, tightened that fitting, cranked and she fired o.k.
Again she ran for about 15 minutes at 1200rpm, then same problem. Engine stops and will not start. I have to ?bleed? the fuel pipe between lift pump and carb as described above to get it going each time. And so the cycle goes on.
I suppose it is sucking air in somewhere between tank and Carter fuel lift pump, but damned if I can find it. The entire pipe line from tank suction to lift pump is only about 6? long, but some of it near the tank is difficult to access.
I will describe the fuel suction system and what I have checked thus far;
- copper pipe fitted inside the tank, vertically, from tank bottom to a fitting on the top of the tank, pipe has a fine mesh strainer on it ? checked the pipe and strainer are clear,
- copper pipe from fitting on the top of the tank into a ? turn fuel shut off valve, - checked, no holes in pipe, fittings are tight,
- Fuel shut off valve - checked, valve shuts and opens o.k, no holes in pipe, fittings are tight,
- copper pipe from fuel shut off valve to filter/water separator - pipe o.k fittings tight,
- Filter/water separator cartridge Quicksilver 35-802893Q01, - fittings are tight, new filter installed and filled up, filter is tight, I have tried to remove the filter base to check it for cracks but the mounting bolts are rusted up and I will need to cut them to get it off. Inlet and outlet pipes are connected the right way round!
- Rubber hose into Carter fuel lift pump - tight no holes,
- Fuel lift pump, Carter low volume type - I have removed this, stuck the suction hose into a 5l tank of fuel and stroked the pump by hand (it is tight but will pump), it soon delivers fuel with each stroke, a good spray each stroke. With the engine running I took the small clear plastic hose that goes between the base of the Carter pump and the carb, there is no fuel spraying out of this (so I think this means the Carter pump diaphragm is o.k), there is a slight suck/blow from this hose at the carb end, but it is dry, no fuel. Filter in the pump is clean and the gasket is new,
I have taken off each piece of pipe and blown through it with air, all are clear.
I really am at a loss as to what to check next. I know the entire pipe line is clear and tight when I pressure it, so I think I might need to try and put a vacuum on the pipe line to see if it is sucking air in, but I am not sure how to do this?
Any advice / help on what to do next or if anyone has experienced anything similar, would be MOST welcome!
