Engine dies after minutes at idle

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russmoke
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Location: Montana USA

Engine dies after minutes at idle

Post by russmoke »

My Moke specifications as I was advised by previous owner, and what I know.
1. 1098 with a 649 full race factory cam.
2. Custom shortened body due to damage years prior to my purchase, side panels have 2 compartments instead of typical 3.
3. Custom (I understand I think) location of petrol tank, and access to fuel pump.
4. Points distributor.
5. Years ago, when first getting Moke operational, I cleaned much sediment out of the tank. The inside of the tank that can be seen today looks very clean, but a scattered rusted appearance is present, although doesn’t appear to be of concern since the cleaning.
6. Electric fuel pump, with few miles but now about 10 years old since install. No noticeable change in engine operation since installed.
7. Two Fuel filters, one between tank and pump, and one between pump and carbs. The filter in the engine compartment is horizontal in line, between the bulkhead and the carbs. The pump is mounted to the body at the space in front of the tank on the left side of the body, with the filter fitted vertically in the line between the tank outlet and the pump intake. See photo 3: which shows the upper third of the filter is air.
8. Petrol intake has a plastic strainer at the intake. I can't tell presently if it is somewhat plugged, because tank is full. I found this in the Moke Club Forum: “Fuel tank leak. by Tim » Mon Nov 15, 2021 22:11
………… Some Moke tanks have a little plastic strainer in the end of the intake that the lining will seal up. I'm told you can poke them out with a bit of wire fed in through the fuel outlet after you apply the coating.”
Questions about this strainer: see photos 1 &2 that indicate the location in the tank.
a. Has anyone got definite information about how to safely remove, and maybe replace this strainer?
b. Is a similar strainer still available in the market place? What is the description and source for such a strainer product?
9. Duel HS2 carbs. I'm not skilled at adjusting the dual carbs, but have done reasonably well on another HS 2 carb Mini Pickup with an 850 cc engine. I'm getting more knowledgeable about getting the adjustments made on dual carbs for both fuel mix and idle. But I'm definitely not an expert.
10. Recent (winter) carb rebuild kits installed.
11. Operation before rebuild, difficult to maintain idle, impossible cold, and better but not steady when at operational temperature 180 F. Last year the symptom of increasing idle speed, or dying at idle worsened. Thus the decision to do the rebuild kit. I've done a similar rebuild kit successfully on another HS 2 dual carb Mini Pickup. The engine always needed a higher than normal idle setting, I assumed because of the type of cam. During the final drives last year I would need to give the accelerator some taps to keep up the RPMs when at a stop temporarily. Normal street acceleration was acceptable. During heavy acceleration engine would sometimes cut out at higher RPM at about 4500-5000.
12. Since the rebuild, I've only been adjusting fuel mix and idle, nothing on the street yet. I found a good combination between rich/lean and idle speed, that needs 1000-1500 rpm to maintain idle. More than one test with engine at operational temp for up to 15 minutes, and then allowed to idle. Idle was perfect for two to five minutes and then the engine would die. It was like the engine ran out of petrol. There was plenty of petrol.
13. A Moke Forum discussion: Fuel Starvation, Post by PJ » Sat Jun 18, 2011 8:17. That discusses “A very small leak between the tank and pump (above the level in the tank) allows air in and the fuel to drain back from the pipe into the tank….“ “Refilling the float chamber manually….”. I’m able to start my Moke with the use of the choke.
14. Later in the same Moke Forum discussion this: “Exactly as PJ reckoned except that it is more likely to be a leak of the fuel pump seal.” I’m not sure this describes my issue.
Questions summary:
A. Questions about this strainer: see photo that indicates the location in my vehicle.
1) Has anyone got definite information about how to safely remove, and maybe replace this strainer?
2) It is a good idea to have the strainer?
3) Is a similar strainer still available in the market place? What is the description and source for such a strainer product?
B. Remove the vertical filter in the rubber hose line between the tank and the pump intake? I think it wise to have a filter between the tank and the pump, but maybe try to keep it horizontal? Or try remove it entirely, and thus only a hose line between the tank and pump?
C. I determined the rubber hose was initially installed in 2011, and can easily be replaced, but are the symptoms related to deterioration of the hose? I saw no evidence of any sediment in the replaced fuel line filters.
D. Is there any reason to perceive an air leak? Rather the air gap in the vertical filter suggests that fuel is going back into the tank after the engine dies. See paragraph 12 above.
E. Does it make sense with the racing cam that idle needs to be set higher? Any guidance on how high should be appropriate?
Thanks to anyone with opinion, experience, suggestion, or something of humor!
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Nigel(no top)Sykes
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Re: Engine dies after minutes at idle

Post by Nigel(no top)Sykes »

The only thing I can say with certainty is that the strainer is exactly the same as the ones on minis. Because they were plentiful and usually dead cheap at mini show autojumbles I found it easier to buy a saloon tank, carve it open and use the strainer. Thing is , I don’t know what Saloon tanks go for these days
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russmoke
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Location: Montana USA

Re: Engine dies after minutes at idle

Post by russmoke »

Thanks for the strainer reply. My first try to find one here in the USA wasn't successful, but at that time I wasn't certain what to call it. I'll try again using "strainer" as part of the search.

Nigel(no top)Sykes
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Re: Engine dies after minutes at idle

Post by Nigel(no top)Sykes »

After I wrote my reply I had a quick look and didn’t find new ones available anywhere. I think that was the case when I was looking a few years ago hence the saloon tank butchery
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russmoke
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Re: Engine dies after minutes at idle

Post by russmoke »

After a brief search at three vendors including MiniSpares, I wasn't successful finding a "strainer", a "fuel strainer". A saloon tank is at minimum 192 Pounds. Yikes. No diagram, catalog or manual (1968, 1981, 2003) I've reviewed has any indication for a "strainer". I haven't needed a Moke manual prior to this question, and thus can't verify the "strainer" is unique to the Moke. I've elected not to try remove the strainer thus far, until I'm certain I have a way to replace it should it break during removal, and should it be determined that replacement be needed. I'm researching motor cycle sources.

Nigel(no top)Sykes
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Re: Engine dies after minutes at idle

Post by Nigel(no top)Sykes »

Yep, it’s deffo not cost effective to sacrifice a new tank for that one piece. Also getting it off, out & in then back on might be a bit of a palaver. I was lucky (in a fashion) as the tank had sat for many years and the pick up pipe was well and truly clogged up so I removed it and replaced it making swapping the filter dead easy.
Just out of interest. Both moke parts suppliers list new tanks, it’d be interesting to know whether or not they have strainers on the end of the pick up pipe. If they do then they must be available new somewhere.
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Tim
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Re: Engine dies after minutes at idle

Post by Tim »

Are you sure its fuel starvation? If you take the top off the float chamber after it stops running is the float chamber empty? Remembering that they are never full when you take to lid off because the float takes up some of the volume.

Tim
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russmoke
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Re: Engine dies after minutes at idle

Post by russmoke »

Tim, thankyou, your advice to check the float chamber is well taken, for which I do need to check that. One of the other topics threads about starvation mentioned this advice. You may have been involved with that topic.
Nigel had advised checking with Moke supply sources for the availability of a "strainer". M-Parts has already responded with the following information about the strainer:
Many thanks for your recent email, yes we do have a strainer, but my preference is that we do not fit them when we manufacture new tanks. The reason being when the tank rusts these bits clog up the strainer.

You maybe able to remove it be forcing it off but you will certainly not get another one on there is not enough room. If you are having fuel starvation problems try and clean as much rust out the tank and remove the strainer, and put an inline filter between the tank and the carburettor. You can purchase from a company called ‘Frosts’ a fuel tank lining material, which is a paint application, we have used this with great success in the past. If we can be of any further help please do not hesitate to ask.
Tim, I was hoping to start with the "strainer" issue first, but it is an easy process to check both float chambers on the dual carb set up. That could tell me more, thanks for the reminder advice.
Here in Montana, USA the resources are quite limited for advice and assistance, so I make decisions slowly and move on decisions slowly as a DIYer.
Thanks again,
Russ
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Willie_B
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Re: Engine dies after minutes at idle

Post by Willie_B »

Is your gas cap vented? It should be, otherwise you can create a vacuum in the tank after a few minutes and fuel will stop flowing.
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russmoke
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Re: Engine dies after minutes at idle

Post by russmoke »

Willie, thanks. I believe it is vented, I've attached photos of top and underside views. Additionally the cap doesn't fit very tight, but fuel will not splash out when twisted properly, if I've filled too full on occasion.
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russmoke
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Re: Engine dies after minutes at idle

Post by russmoke »

Nigel, before I get to far along, I want to post the reply from 7ent.com about the "strainer": The Saloon uses a similar screen and some people have accidentally plugged it by having their tanks coated inside. At that point people have told me the only solution is to poke a hole in the screen. It seems to me that if one put an external filter before the pump then the screen would be redundant.
So, a second Moke supply source, this one in the USA, suggests to me that my use of a filter between the tank and the pump, and a filter between the pump and the carbs would be optimal. Thus, I now intend to try remove the "strainer" from my Moke tank.
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Willie_B
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Re: Engine dies after minutes at idle

Post by Willie_B »

There is one breather hole on the underside of the outer rim. Make sure it is not blocked. You can blow in the larger tube on the bottom of the cap and listen/feel for air coming out of that hole.
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russmoke
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Re: Engine dies after minutes at idle

Post by russmoke »

Willie_B. I found the hole, and yes air does flow through it. A little saliva over the hole confirmed that with ease. I had been able to hear air movement, but the saliva finalized the test. Sorry for the spitten image! Thanks so much for the photo. Ah, the nuances of the Moke vs the Saloon or extended Pickup!

To all: Progress report, slow but sure.
1. I've drained the tank dry. I've repositioned with new hose, the filter between the tank and pump, so that the filter is in a horizontal position instead of a vertical position.
2. I've check both float bowls for fuel. Both have fuel in them, with fuel approximately 1/2" below the top of the bowl when the float is slid aside slightly but kept in the fuel. With the float entirely out of the bowl the fuel is about 1" below the top of the bowl. Based on one other conversation I had yesterday, the advisement indicated that if there is fuel in the bowl the pump is working ok. Do you all agree? I'm asking to verify if I understand that guidance.
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russmoke
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Re: Engine dies after minutes at idle

Post by russmoke »

Update: Completed draining tank and spent a lot of time using a small extendable magnet to remove metal sediment in accessible areas of the tank, especially the small well that includes the drain plug. Completed destroying and removing the screen around the "strainer". Repositioned the remaining top and tube of the "strainer" that was still attached to the fuel line in the slot of the baffle wall inside the tank. Fuel added to the tank and adjusted carbs for startup. Started right up, ran well enough to get up to temp. Managed to adjust to suitable idle but again not steady. Reviewed directions further and slacken the camping bolts on the throttle spindle interconnects. Disconnect the jet control interconnection by slackening the camping bolts. Made appropriate adjustments and tightening of the clamping bolts and adjustments to throttle adjusting screws to assure suitable "hiss" in both carbs. Idle very well with slight adjustment to idle screws. I'm not sure if the throttle carb springs need to be replaced. Found a broken wire on the throttle cable that might be preventing the throttle to return to normal position. (I'll correct that, maybe will need a new cable). More tests to come, but looking pretty good. Idle set at about 1500 rpm which seems best for this racing cam, unless someone has advice on that issue.
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Tim
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Re: Engine dies after minutes at idle

Post by Tim »

If there was fuel in the float bowls then it must have been getting through to the carburettors. The float bowls help regulate the flow to the carbs, and if the supply is cut off, the engine will ocntinue to run for a couple of minutes until all the fuel in the bowls is used up.

I'd suggest you try something to dissolve the rust inside the tank. I go my Mini tank pretty much back to shiny metal using citric acid, but there are heaps of other chemicals that will convert the rust and enable you to properly flush it all out. Of course it may find pinholes that you didn't know you had.

Tim
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