Westerbeke W30 surge and die

[skipperpete]

Good luck with the testing, looking forward to hearing that you got it fixed.

[skipperpete]

Oh, fyrfytr33 before I forget, turn off the raw water intake, excessive dead cranking will fill the exhaust with water and possibly hydrolock a cylinder

[fyrfytr33]

Raw water is off until start. Don’t need another headache. Thanks for your thoughts. Nice to have someone to bounce my thoughts off of. My fiancé listens and agrees but I’m not sure she totally understands what I’m talking about. ��

[cr180]

For what it is worth, have had a somewhat different experience. Surge and die on a Perkins was not air but insufficient fuel. Happened in a beam sea and clogged fuel filters. Ok, 5” dp across filter may not be enough to cause problem, but perhaps look for fuel blockage. Not sure what secondary fuel filter you might have, but on the Perkins, it is easy to install gasket incorrectly (since you can’t see it as you are assembling filter) and starve engine for fuel. Had that happen as well. Can also have a plugged up pickup tube/screen in tank.

Good luck.

[cr180]

Should add that I have Raycor 500 fuel filters, and rarely exceed 2.5 to 3” dp. So maybe 5” should be investigated. Maybe all across filter or showing flow resistance in other parts of flow path. I have an electric pump as well, but only use it to polish or to bleed engine. Under normal operation, the on engine mechanical fuel pump supplies the high pressure fuel injection pump. The other thought might be to take a look at the mechanical lift pump, if your engine has one. Could be that it can’t overcome the suction dp.

[cr180]

Last thought. I have a friend who works on boats for a living. He has a bunch of stories about “new” stuff failing. Again for what it’s worth.

[fyrfytr33]

Ok, this is what I found today.

I'm thinking my over confidence could be part of the problem. I talked to someone much smarter than me and after I explained everything his thought is my in-line electric fuel pump is causing a restriction that in turn causes the mechanical lift pump to find a small leak that is not otherwise evident.
So I bled things and started the engine, with the electric pump turned on everything is fine. When I turn it off, sure enough before long I get air in the return line and surging. When I turn the electric pump on sure nuff I get bubbles from the lift pump. This would suggest there is a leak that develops when the mechanical lift pump gets restricted and has to find someplace to suck...air. I am not sure why I don't see very many bubbles in the clear intake line but I suspect the bubbles are small enough that they may not be visible. They do show up on the output side of the filter on the way to the injection pump, thus causing the surging. I thought about blaming the secondary filter but that would mean the injector pump has enough suction to pull air past the gasket on the secondary filter. I understand the injection vane pump does not have that kind of suction. So the governor tries to make up for the shortage and increases RPM's until it can't keep up and the engine dies. Hence the surge.
So what to do? I'm thinking I have no desire to go back to the little lever pump on the mechanical pump. I plan on using a couple diverter valves to isolate the electric fuel pump under normal conditions. Diverting through the electric pump only when priming.

What do you all think?

[cr180]

Originally Posted by fyrfytr33

Ok, this is what I found today.

I'm thinking my over confidence could be part of the problem. I talked to someone much smarter than me and after I explained everything his thought is my in-line electric fuel pump is causing a restriction that in turn causes the mechanical lift pump to find a small leak that is not otherwise evident.
So I bled things and started the engine, with the electric pump turned on everything is fine. When I turn it off, sure enough before long I get air in the return line and surging. When I turn the electric pump on sure nuff I get bubbles from the lift pump. This would suggest there is a leak that develops when the mechanical lift pump gets restricted and has to find someplace to suck...air. I am not sure why I don't see very many bubbles in the clear intake line but I suspect the bubbles are small enough that they may not be visible. They do show up on the output side of the filter on the way to the injection pump, thus causing the surging. I thought about blaming the secondary filter but that would mean the injector pump has enough suction to pull air past the gasket on the secondary filter. I understand the injection vane pump does not have that kind of suction. So the governor tries to make up for the shortage and increases RPM's until it can't keep up and the engine dies. Hence the surge.
So what to do? I'm thinking I have no desire to go back to the little lever pump on the mechanical pump. I plan on using a couple diverter valves to isolate the electric fuel pump under normal conditions. Diverting through the electric pump only when priming.

What do you all think?

See my previous posts. Strongly suggest you have a fuel restriction. Overcome by the electric fuel,pump, but mechanical lift pump cannot.

[fyrfytr33]

I read your posts and I appreciate your help. If you look back at my posts you'll see everything has been replaced. Tank, fuel, vent, pick up, shut off, fuel lines, Racor, lift pump, secondary filter, filter elements, injection pump, injectors, copper washers, everything.

Ran fine for two hours today until I turn off the electric fuel pump, then the bubbles return. Only sucks air when the electric pump is turned off.

[cr180]

Originally Posted by fyrfytr33

I read your posts and I appreciate your help. If you look back at my posts you'll see everything has been replaced. Tank, fuel, vent, pick up, shut off, fuel lines, Racor, lift pump, secondary filter, filter elements, injection pump, injectors, copper washers, everything.

Ran fine for two hours today until I turn off the electric fuel pump, then the bubbles return. Only sucks air when the electric pump is turned off.

OK. Three thoughts. 1) Think key to solving mystery is that engine runs until turn off electric fuel pump, 2) Could very well be that have some air in leakage but main culprit is restricted fuel flow, and 3) as distasteful as it may be, could well have “new” components such as pickup tube or mechanical lift pump defective.

Have suffered pain of similar troubleshooting efforts. Have faith that you will solve this one and others in the future!

[cr180]

Or maybe air in leakage is in electric pump discharge that is in on engine mechanical lift pump suction.

[fyrfytr33]

Thank you for your confidence.

For clarification, tank, fuel, pick up, shut off, vent, Racor filter are all one season old and were working fine prior to engine rebuild. But then the electric pump was there also. I just replaced all fuel lines and clamps thinking maybe I had a leak somewhere.

I have thought about bad parts but can't seem to prove it to myself yet.

I can't see why I shouldn't put the electric pump in a bypass so I can isolate it. Would also work as a back up if the mechanical pump were to fail.

[fyrfytr33]

I'm really leaning to a leak around the electric pump discharge. It seemed the clamp wasn't super tight. I tightened it and it seems better but still getting a little air. Hence my wanting to bypass it and see if I still get the bubbles.

[Uncle Bob]

Originally Posted by fyrfytr33

I'm really leaning to a leak around the electric pump discharge. It seemed the clamp wasn't super tight. I tightened it and it seems better but still getting a little air. Hence my wanting to bypass it and see if I still get the bubbles.

Mabee it is time to eliminate the electric pump from the equation by replacing it with a hose, just short term, and see what happens. Neither difficult nor expensive and will rule it in or out.

[fyrfytr33]

That's what I'm thinking. I was leaning towards putting in the bypass as it's not easy to get in there to the to the pump. Rather just be in there once.