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Showing results for tags 'dpa pump'.
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BMC 1.8 Odd revs increase, cause unknown.
Tracy D'arth posted a topic in Boat Building & Maintenance
Happens very occasionally but I am stumped. Narrowboat presents with 1.8D BMC diesel with weight pad on flywheel, clear prop, no smoke at all from exhaust. This engine I know will tick over all day at 550 rpm. Big prop, hospital silencer. Skin tank cooled Serviced 150 hours ago, fuel filter not changed but inspected. No sign ever of bug. Has been run for the past month daily. No water in tank, fuel separator or filter. Uses 1 to 1.4 litres of fuel an hour. No fuel leaks and no air leaks found on any fuel pipes or filter. Starts instantly hot or cold, without heater. Runs beautifully as it warms up, tickover on dropping revs, 550 rpm out of gear. When cruising, fully warmed up, not overheating, every 10 to 15 minutes the revs will rise from the 1200 rpm cruising speed to around 1500 rpm for 4 to 8 seconds. Then it settles back to normal. If it is dropped to tickover in or out of gear it is too high at around 800 rpm and will not slow down further. The common cause of revs rising on the 1.8 is momentary fuel starvation but this engine will run hard at 1800 rpm without any hesitation for minutes or until the canal runs out of water. So I have ruled starvation out, the tank has plenty of fuel in. Stopping the engine briefly and restarting it is the same but stop it for a couple of hours it is as normal on restart. I have known this engine for some 20 odd years since I rebuilt it. It has done around 6000 hours since without any real problems. DPA CAV pump was rebuilt then and it has had a new lift pump around 10 years ago because the original leaked around the top. It is driving the owner to drink and I don't know what is causing it. I could simply change the injection pump but I would rather establish the cause first. Advice required please before I lose my marbles.- 43 replies
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- bmc 1.8d
- tickover increase
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I have just relocated the final filter fuel on our Perkins 3152 engine (to make for easier access). Whilst re piping it looks as though it would be possible to send the Back Leak from the pump directly to the fuel tank, along with the spill return, but still keeping the air vent on the filter into spill return pipe. I notice the pipe work on the engine, like most, doesn't follow what would be the ideal route (always rise to an outlet) however the installation is working fine; except ---- sometimes a filter change takes more than just bleeding at the filter head and the pump also needs attention.... I think an easier route for air to clear the fuel system, particularly when doing a filter change, could be arranged but I can find no references as to the ideal arrangement for the back leakage pipe. Does anybody have any ideas or experiences please? John