Volvo-Penta 2001 Fuel problem

[Yara]

My Volvo -Penta 2001 has not done any work for the past 2 years. However, it has been started occasionally, and ran normally out of gear. Now that I want to actually sail the boat, it is giving me grief.

The problem: Starts OK. Will respond to the engine control (let’s call it the throttle) and rev up for a few seconds, and then the revs drop to idle, and nothing happens when I move the morse lever to WOT wide open/full speed. Just sits there chugging and bouncing around until I pull the stop control.

The throttle lever normally behaves rather oddly anyway, either side of neutral it flops down to the 8 oclock or 4 oclock position and moves the engine control from there. (Clutch out).

So check the movement of the engine controls. Hard to see, but the throttle lever does move the speed control lever at the engine.

Looks like a fuel problem. Open the air bleed screw on the secondary filter and pump away on the fuel pump lever. Many small bubbles, hardly any fuel. Lots of pumps to get to what appears to be air bled out.

Re-start, and the same sequence. So, it looks like an air in the line problem.

I have no maintenance records from the previous owner, so step one check the fuel.

Extract sample from bottom of tank- no evidence of diesel bug. Decide to change both fuel filters. Primary is standard CAV Delphi 296. Small amount of dirt on one side, but otherwise clean. New seals but short of one for glass bowl at the bottom. (Replacement filter kit only has two large seals.) Interestingly the PO had used two seals on the bottom, one above the other. Replaced with just one.

Tightened all the hose clips between tank and engine.

The primary filter is mounted above the liquid level of the fuel tank, so no flooded suction. Had to pump a lot on the fuel pump, but the glass bowl did fill up nicely.

Removed the secondary filter, and it was full of diesel, and looked clean, but replaced anyway. Pumped the air out again, and nice, non-bubbly fuel came out of the bleed screw.

Started up, and she started readily, but the problem is still there!

Was feeling miserable, cos a reliable engine is critical, and a new one would cost more than the value of the boat. A cry came across the water from my neighbour on the mooring. His near-new, permanently mounted, chained, 9.9hp outboard had been stolen from his yacht! Told him I almost wished they had stolen my diesel engine!

I guess the next step is to renew all the hose fuel lines, however, maybe someone out there has a better idea of what the problem could be. A method of identifying where the air leak is, would be nice. I’m thinking of connecting a hose to one of the extra ports on the CAV filter and pressurising the system upstream of the fuel pump. Could it be a faulty fuel pump?

All ideas appreciated.

 

[Bilgediver]

I think there might be a plastic basket filter in the lift pump as it looks like it has a removable cover. Also check the action of the lift pump. You do not actually pump these pumps . When operating the lever it pulls the diaphragm down against a spring and when you release the lever it is the spring which pushes the diaphragm and pumps the diesel to the engine. If the pump is in good condition and the engine stopped If you pump a stroke and then pump a second time there should be little or no resistance to the second stroke as the spring cannot pump the fuel anywhere so the diaphragm is still in the compressed position if you feel resistance after a very short period then it indicates that there is leakage such as a bad valve or leaky diaphragm . In this case there could be fuel starvation when the engine is running. The better the pump the longer the time before a full stroke resistance is felt on the second stroke.

 

[Yara]

The lever on the fuel pump "flops" down 70% of the travel, with only a short angle with resistance. This happens when the bleed screw is open, so I wonder whether I should try with the screw completely removed.
This is from the service manual. The vent screw is the one with screw driver head. I wonder if I should vent the banjo connection as shown as well, as per illustration? The owners manual only talks about the vent screw.

 

[Bilgediver]

In neither of your two posts do mention about priming through to the injector from the filter. I suspect you cna use either the screw or the banjo bolt to bleed the filter. however following this and afterclosing the bleed scres on the filters you must then bleed to the fuel pump and then with the injector inlet nut slack wind the engine over at half throttle till fuel minus air appears from the slack injector connection. once you have done this you should detect that the pumping stroke of the lift pump is shorter than before.

There appears to be something wrong with your cockpit lever connection to the engine and this needs investigating as the cable should move as soon as the lever moves. usually the mechanism can be sighted to check tis however this is not always possible . It could be possible that there is so much free play that the throttle lever is not moving the speed lever on the engine over its full range of travel from the idle setting screw to the full speed screw.

 

[MoodySabre]

You know that there is a problem with the Morse control. My philosophy is to solve known problems before looking for new ones. Then you can work through the system methodically.

I have only bled my VP2003 using the screw. Sometimes it is necessary to turn the engine over to get lift pump to work properly due to the position of the cam.

 

[Yara]

For some strange reason, the morse control mechanism is located in an extremely inaccessible spot, so I have not been able to check that end. However, even with it's weird behavior, it was still doing the job before. Also, I can see the control arm on engine move as I move the morse lever.

 

[AntarcticPilot]

In neither of your two posts do mention about priming through to the injector from the filter. I suspect you cna use either the screw or the banjo bolt to bleed the filter. however following this and afterclosing the bleed scres on the filters you must then bleed to the fuel pump and then with the injector inlet nut slack wind the engine over at half throttle till fuel minus air appears from the slack injector connection. once you have done this you should detect that the pumping stroke of the lift pump is shorter than before.

There appears to be something wrong with your cockpit lever connection to the engine and this needs investigating as the cable should move as soon as the lever moves. usually the mechanism can be sighted to check tis however this is not always possible . It could be possible that there is so much free play that the throttle lever is not moving the speed lever on the engine over its full range of travel from the idle setting screw to the full speed screw.

The 200x series engines are self bleeding from the secondary filter to the injectors. There's no (simple) provision for manual bleeding.

 

[neilf39]

Possible small split in the lift pump diaphragm which limits how much it can pump? Try connecting a hose to the bottom of the lift pump direct into a fuel container of diesel and start with it below the lift pump and then raise it higher. Remember the fuel will go to the main tank via the return though unless you also route that to the container. Do sort out the morse control. Doesn't it drive you potty when manoeuvring?

 

[Yara]

Thanks Neil. The lift pump seems to work OK as it had enough suction to pull the fuel up from a lower liquid level in the tank and fill the primary filter bowl. However next time I am on the boat I will try tightening the bolt that holds on the pump cover plate.
Strangely the morse lever only flops when the clutch is disengaged. Once the button is in, and the drive turning, it behaves normally.

 

[Bilgediver]

Thanks Neil. The lift pump seems to work OK as it had enough suction to pull the fuel up from a lower liquid level in the tank and fill the primary filter bowl. However next time I am on the boat I will try tightening the bolt that holds on the pump cover plate.
Strangely the morse lever only flops when the clutch is disengaged. Once the button is in, and the drive turning, it behaves normally.

This concerns me. I still feel that your problem could be a throttle problem and if the lever is just falling then IS IT MOVING the speed lever on the engine at this time as it falls. or does it only start moving the speed lever at the time it stops falling. If this is the case then your speed lever on the engine may not be travelling the full range all the way to the high speed stop. There would normally be enough friction in the speed/throttle Teleflex to stop the fall. The throttle is connected with the button both in and out.

Don't forget that a diesel speed lever is just that and will only give full speed if the lever on the engine moves ALL the way regardless of load. This is totally different to a car throttle where if in neutral you can overspeed the engine with very little throttle movement.

 

[neilf39]

Thanks Neil. The lift pump seems to work OK as it had enough suction to pull the fuel up from a lower liquid level in the tank and fill the primary filter bowl. However next time I am on the boat I will try tightening the bolt that holds on the pump cover plate.
Strangely the morse lever only flops when the clutch is disengaged. Once the button is in, and the drive turning, it behaves normally.

I was thinking it is a small split so works OK to pump by hand to bleed but can't cope with the engine running as it will be pumping under pressure. May be nothing to do with it. Besides my suggestion with the fuel container would show if there were an air leak before the pump if it worked with the container low. If that did not work then raising the container may show if it is a lift pump issue.

 

[Bilgediver]

I was thinking it is a small split so works OK to pump by hand to bleed but can't cope with the engine running as it will be pumping under pressure. May be nothing to do with it. Besides my suggestion with the fuel container would show if there were an air leak before the pump if it worked with the container low. If that did not work then raising the container may show if it is a lift pump issue.

It might be possible to check if this is leaking by removing the engine dipstick and seeing if the oil on it smells of diesel oil!

 

[Yara]

One of the great things about this forum, is how all the different minds approach trying to solve a problem. Sometimes the problem is not what it seems, and that is the case here.

FUEL PROBLEM SOLVED
I probably did have a fuel problem, air leaks on the suction side of the fuel pump. Two possible causes, the fuel tank isolation tap, and hose clamps needing tightening. The fuel isolation valve I call a tap because it is a mini globe type valve which screws down from the top. I haven't pulled it apart, but I'm guessing there is an O-ring seal on the handle, just like a domestic water tap.

I think I caused an air leak by forgetting to open fuel tap and pumping away at the fuel pump. That would have created the condition where the O-ring seal on the fuel tap could have let in some air. The other mistake I made was only opening the bleed screw by about one turn. Reading the maintenance manual, it refers to 4 full turns on the bleed screw. Once I followed that, the fuel gushed out, and no more bubbles.

IT’S THE SPEED CONTROL LEVER!
Those of you who pointed out a link to the speed control, were in the right direction. Turns out that the speed control arm on the engine was/is slipping off the shaft, and that caused the revs to drop. Hopefully you can see in the attached photo, that there is a weird spring washer between the speed control arm and the stop lever spring.

Reference to the only parts drawing I can find shows the arm, item 33. I should have twigged that that weird spring washer was not original, given that the control arm was not sitting straight. So, when I rev the engine, the speed control arm drops into a groove, and disconnects. No idea why there is a groove on the shaft.

Now the problem needs a solution. Of course, the speed control is hard up against a bulkhead, with limited access. Reference again to the diagram, it looks like I need washer number 34 which is described on a German parts list I can't find again, as a double split washer. Hopefully I can somehow remove the nyloc nut item 37, and the stop lever controls, so that I can fit washer number 34.

Dear brains trust, is there anybody out there who can tell me exactly what item 34 double split washer is, so that I can try and source something suitable? If I could find that German parts list again it might even be available, but I won't hold my breath. Could it be some flexible washer that drops into the mystery groove?

Any ideas?

 

[Bilgediver]

Is that spring washer preventing the lever from moving far enough along the shaft and preventing it from correctly engaging with it? You have two levers on a coaxial pair of shafts so it must be possible for both to fully engage with their respective shafts . The washer in you photo looks thicker than in the drawing and could be preventing the lever furthest from the engine engaging with its shaft. Get some thinner washers if this is the case.

Many thanks for your feed back. The seal on the fuel outlet from the tank should not let air in. on some valves there is NO seal there especially if the operating wheel handle is star shaped as this may be a Saunders valve especially on older Westerlies and there is a diaphragm in the body that seals the fuel from the atmosphere.

Sometimes telepathy helps when responding to forum questions

 

[Yara]

The plot thickens. Found another parts diagram which shows the metal circlip/washer which I have, instead of the flat double washer. The other thing which is not clear is what locates the whole concentric shaft assembly in the side plate. It amazes me that VP would design such a dodgy arrangement on a critical component like engine speed control.
I am wondering if the double washer item 34 is a wear component, and was replaced by someone with a later design circlip which is not wide enough for the groove in the shaft.
The speed control arm locks on the shaft when it is close to the side plate. (Left in the picture)