Perkins 4-108 Power Loss and Shutdown

[RJ86]

Hello all-

I was motoring upwind South of Half Moon Bay at about 3000 rpm last week when the engine in my 1979 Gulfstar sailboat surged briefly, and then shut down completely, almost as if someone had pulled the shutdown lever. I remember saying something like "Oh, darn," because with the wind against us, and forecast to die off at sunset, we definitely needed the engine to get to San Francico that night.

I checked all of the obvious things: fuel quantity, the filters (Racor primary and Baldwin secondary), and everything seemed normal. I then engaged an electric 'bleeding' pump that was added on to the fuel system, in case the mechanical lift pump had failed, but that didn't help.

Right now, I'm looking at the injection pump thinking.... "Gosh, THAT looks like fun! And I'm sure it'll be inexpensive, too!" So I was hoping for any ideas that might save me unnecessary work and expense.


Thanks in advance-
Rick

[btrayfors]

Need more info to be really helpful.

The brief surge suggests fuel starvation or air in the fuel line.

Could it be an overheat or low oil pressure shutdown? Was water flow OK?

BTW, IMHO 3,000 RPM is a bit fast to be running a 4-108. Most are prop-ed to cruise at 2200-2600 RPM. I run mine at 2300-2500 RPM max.

Bill

[RJ86]

Well, thanks... but an overheat on this boat does not shut down the engine, nor does low oil pressure. Moreover, all of these parameters were normal.

In fact, I've never had a boat that had auto shutdown for high temp or low oil pressure. That's why I'm focusing on the fuel system.

The power loss was quite abrupt, and was not accompanied by any other abormal indications, aside from the brief surge.

Bleeding the fuel injection system has not provided any relief. Fuel starvation? There's an idea! But why? I was wondering if anyone had experienced sudden power loss following injection pump failure, or anything with similar symptoms.

Rick

[capttman]

There are three reasons for your problem on a 108. The gasket on the secondary fuel filter has been compromised by the lack of lubricant in the modern diesel fuel. Also check top o ring on the bleed screw. Micro crack in the fuel lines. But more than likely if you have run a lot of fuel through it in the last few years the seals in the injector pump have eroded due to the low sulfur fuel. Do you see any weepage beneath the pump? A rebuilt pump runs around 800.00. plus your core. you will be charged for the core until they determine if it can be rebuilt. This is a time consuming job where you probably need to remove your heat exchanger and exhaust manifold to have clear access to all the bolts. Hope it helps.. Past few years i probably changed 12 out due to low sulfur fuel.. Anyone reading this should make sure you run an additive at 1.5 times recommended level

[RJ86]

Thanks Capttman...

One more question before I start tearing this thing apart: In your opinion, would these sorts of problems account for the sudden and complete loss of all power while running at cruising rpm? I mean, that's the part that threw me... the thing went from running fine to dead in the water in about 2 seconds. I would have anticipated rpm decay or some other warning signs in advance of complete shutdown with pump failure or almost any other malfunction, except maybe just running out of fuel or something like that.

Thanks again-
Rick

[SkiprJohn]

Have you tried by-passing the filters with a temporary and small amount of fuel in a gas can filled with clean diesel to see if it'll run without going through your existing fuel lines and filters? Did you bleed the injectors to try to get it started again? I've had what you describe happen on my 4-107 when I sucked a tank dry and it clogged my fuel filters and also on a 4-236 when the fuel tank selector handle got pushed to a slightly off position by accident in the engineroom. In each case I had to bleed the engine at the injectors in order to get it running properly again.
Good luck in sorting this out. It sounds like a fuel starvation problem.
kind regards,

[donradcliffe]

It sounds like classic fuel starvation. Don't rip anything apart until you are sure that the engine is getting fuel.

If you have not already replaced the filters, do so. Then rig up an outboard fuel tank with diesel in it to the primary filter, and use the squeeze bulb to bleed the system.

If you have never bled your fuel system before, you need to bleed it again, until you are absolutely sure that you have fuel. Start by cracking the bolt on top of the secondary fuel filter, then go to the one on the injection pump, and pump a lot of fuel through. Finally, loosen the fuel connections on the injectors and turn the engine over (be sure to shut off your raw water valve) until you see fuel squirting out (if it doesn't squirt, you need to bleed upstream some more).

[RJ86]

Thanks for the advice. I had lots of fuel in the tank when it died. So I naturally switched fiters on the Racor, changed the secondary filter, and bled the system using the electric pump. I'm getting fuel to the injectors, but I'm not sure at what pressure.

I'll try supplying fuel from a portable tank directly to the lift pump, in case there's some small leak in the fuel line somewhere. Otherwise, aside from changing the injection pump, I'm out of ideas.

Thanks again-
Rick

ps- thanks for the tip about the raw water sea-cock! I didn't think to close it before cranking the engine.

[Capt Roy]

Hi Rick,

I'm very curious, what happens when you attempt to start the engine at this point? Does it sputter a bit then quit?

Last summer I was out enjoying a harbor cruise with 2 lovely ladies and as I crossed our main channel my Perkins 4-108 low line reved ever so slightly then shut down. I tried to restart with no luck at all.

We coasted to the opposite side of the marina and I managed to land her at an open guest dock at the park. I then spent an hour or so changing both filters, bleeding the lines, etc., but it had no impact at all. Had to get a tow back to my dock as I hung my head in shame.

After much work, a new injection pump, and injectors we were no closer to getting it running. I would crank it but it would just sputter a bit and do nothing more.

The final fix? Turned out to be a full blockage in the lift on the exhaust. Evidently something had corroded and broke loose in the lift and totaly blocked the flow of exhaust. This in turn built up back pressure which would not let the engin take in fresh air. The tip off was when the mechanic slowly turned the engine by hand, we would get a whooshing sound from the intake as the intake valves opened and, what should have been exhaust, exited the intake.

New exhaust and lift intalled and VVVRRROOOOMMMMMMM, started right up. The symptoms had been just like fuel starvation and even fooled the mechanic for a time.

[DeepFrz]

Could be a blockage in the fuel line. Been there, done that.

[shakey doug]

G'day,
Have you cleaned the filter screen in the top section of the lift pump?.Make sure the hp fuel pump stop lever return spring has not brocken or jambed the stop run lever. when using an electric bleed pump both bleed screws on the fuel pump must be open, fuel should run clear free of any air before retightening then open injector leads at injector end apply full throttle crank over until spurts appear then close, now ready to start. Remember easy--none cost FIRST.

[RJ86]

Thanks again Doug and Roy and DeepFrz (et al.)....

When I've tried to start it, I had no joy at all until I gave it a shot of ether... then it ran for a few seconds (hooray!) but then promptly shut down. Subsequent starting attempts were to no avail.

I then inhaled a few shots of ether myself, just to get my mind right. That helped a lot. But the engine was still AFU.

My first mistake was sailing with 2 ulgly men instead of 2 lovely ladies, I suppose. I will definitely check the exhaust and lift. Thanks Roy.

I'll also double check the filter screen and stop-lever spring, etc. Thanks Doug. Good luck with the shakes.

I'll try to supply fuel from another source, to check for a blockage in the fuel line. Thanks DeepFrz.

If I ever get this sucker running, I'll letya know wtf it was!

hasta luego-
Rick

[Capt Roy]

Rick,

Don't use ether to try and start it. Not good for diesels. Use WD-40, it works and lubricates as well.

[Dynamo1181]

At the fuel inlet to the injection pump, there is a very small filter. This a last ditch effort filter that is not obvious and sets inside the pump; but the filter is accessible after removing the line. Its hard to imagine this filter being completely blocked unless there was a catosrophic failure of the primary and secondary filters.
A

[GordMay]

Fouled prop'?