Volvo D2-40 Fuel Starvation

[Rolloh]

Re: Volvo D2 diesels - fuel starvation
I'm going to jump in after reading all that has been said and provide some info. as to the fuel starvation issue and answers I've came up with.
First, the hand prime pumps fail, this was told to me by a Volvo dealer.
Second, he has seen them right out of the box fail to work, they leak air.
Third, I will be picking up a new pump up tomorrow, after its been checked to work and see how long it lasts, the original lasted for four years. However after changing filters out a few times the problem (air) in the system became apparent. The last straw was it would not hold a prime to even start the engine. So I will keep the group posted as to the out come of the events that lead up to this posting.
Rollo

[Rolloh]

Well back again still with no answer to the question. I've checked everything possible with a brand new vacuum gauge, no leaks from the tank to the inlet of the engine. Changed out the priming pump housing with the bleed screw put sealant around the hand pump crimp fit where the dealer said it may leak, replaced with new every thing from the tank to the engine and still have the same problem. I was told as well to put a fuel pump inline prior to the filters to boost the pressure (didn't do it yet). I installed a vacuum gauge as well and its pulling 1 1/2 pounds of vacuum which is where it should be, when its running. Don't add a larger fuel line, it will only make the engine pump work harder because of the amount of fuel volume its trying to pull or lift. The intake for the fuel is 3/8" so that is what is required according to the Volvo Dealer. I still have the same symptoms as before. I even after pulling the inspection cover used a drill pump and pulled fuel from the bottom of the tank just to see what was down there, nothing. I put fuel stabilizer in the tank once a year and burn about 30 gallons annually. Even had it polished a few years back when I first bought her and the fuel looked great, even to the guys whom came to the boat and did it. Costly if you do it by yourself, my neighbor went in with me so it didn't sting to bad. But here we are, same old problem, I'm totally at a loss at which step to take next. Short of pulling it out and buying a new engine, this one has 279 hours on it, what next?
Rollo

[CarinaPDX]

I have a D2-40 sitting in the cockpit for me to install - 'hope I don't have this problem. Do keep us informed.

I think the primer/fuel pump is a Racor part, so if you are out of warranty you might start buying replacements there for a lot lower price. I plan on doing what I have done for 3 decades: put an outboard squeeze bulb in the fuel line before the off-engine prefilters. This makes it easy to change filters and top up the fuel, as well as bleed the engine. If the primer pump on the engine becomes a problem I would replace it with a filter without the pump. I don't like the Volvo part as there is no drain for water, although the prefilters should have dealt with that anyway. I would prefer a permanent metal bowl with replaceable element, drain, and no pump.

How far below the engine is the bottom of the tank? The spec for this engine is 0.8m (31.5") to the feed pump inlet on the engine - beyond that you can expect to draw air into the system. The solution is to either use a day tank, and a transfer pump for fuel in lower tanks to put the fuel in the day tank, or add an electric fuel lift pump (with adequate suction and capacity) on top of the tank. I use a day tank, which solved air problems with the old engine. Either way, the fuel lines/filters/pumps will not have a high suction; no matter how well everything is sealed together, high suction will draw air in at some point.

Other than that I don't have anything to offer - perhaps once I am up and running I will have some ideas.

Good luck. Greg

[Rolloh]

Well I went long enough to take out two motor mounts that I have to replace from the vibration once it starts. I have at this point changed the entire fuel feed system twice, took out one of two Racors, new fuel line again, one Racor filter, did a vacuum test on tank fittings and pick up tube, all good. Put clear hose and went about two feet before the engine and still getting air. It ran with my other system for almost three years before this problem arouse.
I cleared the fuel line to the tank and used the hand primer on the filter housing and still got air and fuel, it would not pull that last little bite of air out. However, it starts and runs well, going to leave it over night and see what happens. It pulls 1 1/2 p of vacuum unless the filters start to plug, that's what that gauge is for, when it runs properly..... I don't get it !
Rollo

[Rolloh]

Got it, lowered the Racor and got gravity working, problem is solved. 0 on the vacuum gauge. Runs as new again. Was running on 3 1/2 on the gauge, with a check valve. That alone takes 1 1/2 of vacuum, took it out as well. Zero is better.
You will love this power plant and its efficiency, I looked at the others before purchase, and this one if memory is correct the torque curve comes in lower and drops off latter.
Enjoy, just go low as possible with your filtration system.
Cheers, Rollo