new-to-us 2008 Hunter 36 with a 3YM30. Why would a diesel that has run perfectly since we acquired the boat this summer suddenly not start when hauled for the season? Engaged a local diesel guy to winterize, he reports that the engine starts then stops within a few seconds. Fuel is not shut off.
winterizing puzzle
- Thread starter George Braun
- Start date
Diesels need three things to run: compression, fuel and air. It's not compression, engine was just running fine. Probably not air, you can check to make sure there are no obstructions. So that leaves fuel. Some problems you can have with fuel: contaminated fuel (especially water), air leak causing air in the fuel stream, fuel pump not providing enough pressure, the high pressure fuel pump (just before the injectors) not providing enough pressure (this is the most expensive but least likely problem). Draw some fuel from the tank into a clear vessel and make sure it looks good. Check all you fuel hoses for cracks, tighten up all the clamps. You can check the fuel pump ability when you take a sample of the fuel by disconnecting a hose and using the pump to fill the vessel. It should be a solid stream with no "spitting".
Easy way to check if problem lies with fuel pump, air or contaminated fuel filter is to get a jerry can a clean fuel, put a rubber hose in the can and attach the other end to the inlet of the lift pump. If the engine starts and then runs without stopping, then you know your problem is from the tank to the pump, and not with the engine itself.
Hi George. Had a similar problem with our Onan Genset Kubota diesel awhile ago. Would start, but only run for a bit then sputter to a stop. There was a single conductor wire that led to the lift pump that had a broken plastic butt connector. Replaced it with an inline crimp connector and have had no problems since.
An earlier instance turned out to be a clogged two micron canister fuel filter. That only cost me the price of the filter; about five bucks. Two micron was over kill, so went with a six micron spin on cartridge. In both cases the engine had plenty of clean fuel and the pickup tube was close to the bottom of the tank.
In addition to the engine fuel filters, both the main propulsion and Genset have ten micron Racor filters between the engine and tank. Your symptom sounds more like a fuel issue rather than air.
An earlier instance turned out to be a clogged two micron canister fuel filter. That only cost me the price of the filter; about five bucks. Two micron was over kill, so went with a six micron spin on cartridge. In both cases the engine had plenty of clean fuel and the pickup tube was close to the bottom of the tank.
In addition to the engine fuel filters, both the main propulsion and Genset have ten micron Racor filters between the engine and tank. Your symptom sounds more like a fuel issue rather than air.
thanks to all for the suggestions and input. The guy hired to winterize the 3YM30 has gotten it done, and the rest will be postponed til spring. Oil and filters change already on the calendar then, and some electrical exploration in between, as previous owners have added some DC wiring and I want to explore what they did - un-switched powered TV antenna at the masthead for a TV that no longer exists, evidently un-switched radar power line up the mast but no emitter or display installed, carbon monoxide alarms all over the boat where fans belong, and old power and signal lines for a binnacle mounted chartplotter that was upgraded in 2021 just before we bought the boat, so now have extra wiring in the binnacle. Opening the breaker panels will be an adventure I'm sure. Will just add the engine panel to the list to check all the connectors and wiring for issues.
Thread drift question - I don't particularly like the push-to-reset breakers Hunter uses for a bunch of DC equipment in their factory distribution DC panels, would rather have proper breakers. Has anyone swapped them out? Issues? Concerns?
Thread drift question - I don't particularly like the push-to-reset breakers Hunter uses for a bunch of DC equipment in their factory distribution DC panels, would rather have proper breakers. Has anyone swapped them out? Issues? Concerns?
Murphy again! Clogged filter ?
I had a cast iron intake manifold on gas engine break while I was putting its twin down with fog. I knocked out the Welch plugs drained the exhaust removed the water tower and thermostats. Not the best practice leave a motor open but no choice.I hate putting in fresh oil only to put the boats away for winter but that’s the rules
I had a cast iron intake manifold on gas engine break while I was putting its twin down with fog. I knocked out the Welch plugs drained the exhaust removed the water tower and thermostats. Not the best practice leave a motor open but no choice.I hate putting in fresh oil only to put the boats away for winter but that’s the rules