Need help: Fuel flow problem

[Daktari]

The details:

'65 Series IIA 109.
Weber 34 ICH carb.

The problem:
Engine idles fine but stutters and stalls under load. The problem began suddenly back in the winter and hasn't been resolved.

So far I have disassembled the carb and cleaned it completely and ruled that out as the problem. When idling the fuel filter container is about half full of fuel, but after driving down the road a few dozen yards and experiencing the stuttering and near-stalling, the fuel filter container has very little fuel in it. So next in line as a culprit is the fuel pump. BUT . . . the part that should be the fuel pump looks nothing like what Rovers North is selling as a mechanical fuel pump. What I am seeing looks like the attached images.

It doesn't have the glass reservoir on the side like the mechanical fuel pumps pictured in the Haynes manual or the catalog.

What is this part?

[artpeck]

The pump....not a clue. Hopefully someone else will recognize it. The problem....could be the pump isnt keeping up. Could also be a blockage on the filter screen on the intake tube in the tank or vacuum on the tank. Try taking the gas cap off and that will rule out a vacuum. Then pull the intake tube from the top of the tank. Other than that your fuel pump is a place to look or a blockage in the line.

[SafeAirOne]

Diesel pumps don't have the glass sediment bowl. Looking at your pic, you've got an STC1190 diesel fuel pump, including the spacer to make it work properly:

http://www.johnrichardssurplus.co.uk/content/images/xxl/stc1190_002.jpg

[Les Parker]

This is pic of the 2.5 Fuel pump modification that Landrover used when the original pump (549761) became obselete.
RN used it for several years as an upgrade/replacement until the Proline PLC349 Fuel Pump became readily available.

The fuel pipes needed to be cut as the inlet and outlets for the new style pump had metric threads instead of the original standard threads.

To fit the PLC349 Pump, you would would need new fuel lines (tank to pump and pump to carb.

Hope this helps.

:)

[stomper]

I have the same fuel pump on mine. You can unbolt it and check to see if it creates a vacuum when you pump the hand lever, or just undo the carb line at the pump and check to see if you can draw fuel with the hand lever. My guess is the draw tube or the fuel lines. I replaced my lines with rubber line by the length from the local autoparts store, the ethanol in the fuel deteriates them over time.

[rosims]

Is the diesel pump better than the Proline pump? Thats what I beleive my problem is. I'm having a similar issue, except i have a new (less that 400 miles) Pro line pump.

[Les Parker]

:)RTC6806 Fuel Pump RN used to offer, FYI http://www.lrseries.com/resources/user/7ddcf9262f8f3bd864991a1663ce27b723bb298f/RTC6806-PETROL-FUEL-LIFT-PUMP.jpg

[Daktari]

Thanks for the good advice from each of you. I'll check the pump and the fuel lines. I think I have gotten some ethanol fuel in the past couple of years (quite by accident) and that may have caused some problems in the line and/or pump.

Thank you.

[Daktari]

So, I'll check the existing fuel pump and lines. But if I need to replace the pump, forget about this older (diesel) fuel pump and just go with PLC349 and new fuel lines? That's great.

[SafeAirOne]

I think I have gotten some ethanol fuel in the past couple of years (quite by accident) and that may have caused some problems in the line and/or pump.

You are fortunate to live in a place where you can "accidentally" use ehtanol-laced gasoline. Everyone around here is FORCED to use the stuff each and every time. I don't think a couple of inadvertent uses would harm anything--I believe it's more of a long term thing and everyone in my state with an older car is involuntarily participating in the experiment to find out for sure.

[Daktari]

So I still need help with this issue.

As I said in my original post, I have completely disassembled and cleaned the carb. I have also gotten the PLC349 fuel pump (petrol) from RN and fitted it, after removing the diesel fuel pump that was on the truck. The fuel lines in and out that were hooked up to the diesel pump threaded perfectly into the new petrol pump. I am not sure if I got the rocker arm aligned properly with the cam inside the engine.

However, now the engine runs for about a minute and stalls. If I prime the pump with the hand lever the engine starts easily, but I don't seem to be getting a consistent fuel flow. At least with the diesel pump the engine would idle. A local Land Rover mechanic suggested a blockage in the line, but I don't have a good idea about how to check that.

Any new ideas?

[SafeAirOne]

Well, it sounds as if your engine runs till the fuel in the carb bowl gets depleted.

I would disconnect the feed line from the tank and the fuel pump and check that there is no obstruction in the line. Once you verify that there is no obstruction in the line, remove the uplift tube from the tank and make sure it is intact and clean out the fine mesh screen on the bottom of the uplift tube and check to make sure flow is unimpeded through the uplift tube.

Reassemble it and check to see if you are getting fuel flow. One of those small, clear fuel filters installed in the line between the pump and the carb is the easiest way to do this. If after several seconds of cranking there is only a tiny trickle of fuel visible in the clear filter, the problem is upstream. If the filter fills about halfway with fuel, the problem is downstream. I don't know a whole lot about Series carbs, but if there is a strainer on the inlet, I'd clean that, then start thinking about checking the float valve.

Note that the spacer block between your old fuel pump and the engine is necessary to get that style of pump to operate correctly, but should be omitted if you have changed back to the original-style pump. Also note that replacement land rover fuel pumps have developed a reputation of being unreliable right out of the box, so you might also plumb in a long piece of fuel line to the outlet side of the fuel pump and stick the other end in a fuel can (or back into your fuel filler) and watch to see if it pumps a healthy amount of fuel while somebody cranks the engine.

Oh, and not to ask the obvious, but is there fuel in the tank?

[bkreutz]

If you can get it to run by using the hand priming lever, that tells me the pump is actually working, if it was an obstruction, that would not work. Either the arm isn't contacting the cam lobe, or the lobe is not egg shaped any more. Try adapting a hose to the outlet of the pump and run it into a catch can, crank the engine and see if it's pumping fuel, I suspect that it's not. I'm not blaming the pump because if it was bad, you wouldn't get any fuel by pumping the priming lever.

[Daktari]

Note that the spacer block between your old fuel pump and the engine is necessary to get that style of pump to operate correctly, but should be omitted if you have changed back to the original-style pump.

Oh, and not to ask the obvious, but is there fuel in the tank?

Ah, yes. The spacer block. I did not remove that along with the old diesel pump, but rather installed the petrol pump right on top of the spacer block. I'll bet you the rocker arm isn't contacting the cam inside the engine. How about I take off the spacer block and see what happens.

Yes, there's fuel in the tank, and I already have a clear fuel filter canister with a paper filter in it. I can see clearly how much fuel is in it, and when I work the pump lever several times I get a little fuel in the filter canister (but not a lot).

The truck was running brilliant up until a few months ago when it just didn't want to go under load. Idle yes, move in gear, no.

Let me remove the spacer block and report back.

[Daktari]

Got it. Removed the spacer block and refitted the fuel pump. Ah, contact with the cam! Now the fuel is flowing properly, I'm back to idling well. Now it seems to be missing on one or two cylinders. *sigh* That's a topic for another thread.

Thanks for everyone's feedback.