Loss of power? - Land Rovers Only

Nanoose · 08-14-2009, 02:30 PM

The truck seems to run fine at idle. I've tuned it and and timed it and didn't find anything grossly out of whack. But the problem that made to think it to tune it in the first place is still happening.

Once I get moving and hit the accelerator the engine seems to die until I take my foot off the gas, and I get the occasional backfire too. I don't think it's electrical - unless it's got to do with the vacuum advance. It seems more like a fuel problem to me.

It's not RPM related. I can be going down a hill with it in gear and get happily motoring to any speed, it seems more related to acceleration.

I've cleaned the fuel filters, set the carb, cleaned the jets, and generally mucked about. I also took apart the accelerator pump and the membrane seems fine - no holes - although I did notice that with the engine idling that moving the accelerator pump by hand had no appreciable effect.

So...any thoughts? I guess I should adjust the valve tappets but haven't got a replacement gasket handy so am holding off on that job...

Thanks for any advice!

Dave

PS. It's the original Solex carb on a Series 1 engine.

pickuprover · 08-14-2009, 03:54 PM

redo the point gap and timing.... Then readjust your carb... Make sure you check the inside of the distributor cap for carbon lines. As well, check to see if the contact points on the cap are in good shape (mine did similar thing when my distributor bushing was worn out causing the spindle to wobble, causing good spark at idle, almost no spark when it tried to wind up as the rotor was wobbling. Eventually figured it out because one side of the cap had paper thin contacts, and the other side looked like someone took a mig welder to them....)

Alot of times it seems like a fuel problem when it is in reality a spark problem. If you are not getting a good enough spark, when you add gas, it basically floods the engine. Have a beer, take acouple of minutes off, and start with the basics. Follow the green bible's tune up section. Start with the timing/distributor setup. Then move to the carb. As well, check to make sure that you do not have a warped carb as that coupd cause your symptoms.

Nanoose · 08-14-2009, 09:53 PM

Hey Andrew,

Checked and re-checked the timing and gap. still the same symptoms. Too dark to do much more now. I'll fiddle with the carb tomorrow. I've just recently gotten the truck and one of the first things I noticed was a fuel leak from the carb at the banjo fitting. I'm wondering now if there are other things that may not be tightened up. I'm assuming that a warped carb would be sucking in too much air?

thanks for the help!

Dave

mbrummal · 08-14-2009, 10:09 PM

If the accelerator pump doesn't do anything, that is probably your problem. If it doesn't enrich the mixture to cover up a "big hole", it will bog down and backfire. My old Camaro did the same thing when the acc. pump was messed up.

Nanoose · 08-14-2009, 10:19 PM

Hey Mason - I kind of wondered about that...I also have just realized that I've got a mechanical fuel pump too? One thing I've found odd is that when I turn the key to "on" I hear the electric pump but it never shuts off. If I let it it will run for a minute without slowing. Shouldn't it stop after a bit?

Much to check...

Dave

Nanoose · 08-14-2009, 10:20 PM

I've been looking but can't find much in the way of spares for solex carbs. The membrane in the accelerator pump isn't very elastic and I'm assuming it should be. Think it's a bad idea to fabricate one?

mbrummal · 08-14-2009, 10:37 PM

Quote:

Originally Posted by Nanoose

Think it's a bad idea to fabricate one?

probably wouldn't work. I've never seen the carb on a series LR, but it could be similar to a holley (again, not sure at all). You could see if it is anything like the one in the solex.

mbrummal · 08-14-2009, 10:38 PM

Quote:

Originally Posted by Nanoose

Hey Mason - I kind of wondered about that...I also have just realized that I've got a mechanical fuel pump too? One thing I've found odd is that when I turn the key to "on" I hear the electric pump but it never shuts off. If I let it it will run for a minute without slowing. Shouldn't it stop after a bit?

Much to check...

Dave

It has an electric pump? in the tank?

It is probably a lifter pump to feed the the mechanical pump, right?

I wouldn't worry about it running, it isn't controlled by a computer.

Nanoose · 08-14-2009, 10:44 PM

The manual talks about a mechanical pump but I think it's actually the electric one. Mine is mounted on the drivers side, just forward of the dash. I looked and can't find anything that looks like a mechanical pump between the fuel pump and the carb. Sorry - is the picture you posted from a Holley carb? I can take a photo in the morning and post it.

Dave

mbrummal · 08-14-2009, 10:47 PM

That pic is the acc. pump diaphragm from a holley. Does the diaphragm in the solex look anything like that?

Have you tried finding a gasket kit for the solex or is nothing really available anymore?

Nanoose · 08-14-2009, 11:15 PM

It looks pretty similar to the photo. I've spent the last hour or so trying to find a kit. I think buying a new Holley carb is less expensive than a Solex rebuild kit.

pickuprover · 08-15-2009, 06:17 AM

Chances are, at some point the mechanical lift pump (which will be on the oil filter side of the engine below the distributor) stopped working and a previous owner bypassed it and put in a electric pump. Fairly common as some people want fuel pumps that can be bought locally.

Not really sure what is available for the solex. Most people end up using a weber 34C (I believe that is the one you want). Try calling your Rover supplier (assuming you have found one by now for parts...) and seeing if they carry any solex parts. I know the one I use does not (however I had a zenith and now have the weber carb.)

Here is the parts page from my supplier for fuel systems. Wise Owl Innovations Incorporated - Land Rover Parts

Dap Inc lists a solex carb in there parts manual Catalogs for Land Rover D.A.P. download it, go to fuel sytems and it lists solex. So presumably they would carry a rebuild kit for it.

Rovers Down South has a rebuilt solex listed Land Rover Parts . As well they have a rebuilt kit for the SU carb, which I believe is the same as the Solex.

Hope this gives you a starting point.

Before you buy the new carb, check the spindle in the distributor. That is why I havea spare weber carb now......

Smokey Mountain Man · 08-15-2009, 09:18 AM

Have you cleaned the pickup tube in the fuel tank? There is a fine screen on the end of it that can get clogged with gremlins. I understand that Rovers North has rebuild kits for the old style solex carbs. another thing that could be going on is the float valve is sticking. Take the top of the carb off, undo the floats and remove the little pin. Then shoot some carb cleaner through it and while your there shoot all the holes. Watch yourself though that stuff stings when it gets in your eyes.

Nanoose · 08-15-2009, 11:20 AM

Thanks guys - I think I'll be ordering parts today!

Dave

Nanoose · 08-15-2009, 11:26 PM

Today I took apart the carb - cleaned everything really well. Then went for a test drive. The mistake was going too far in one direction. Took forever to get home. Still the same symptoms. RATS!!! Time to call my buddy the mechanic. For some reason I think it's something easy that I'm missing...but the problem seems to be worsening. The one thing I did notice tonight is that if I let the truck sit for a few minutes it would fire up and run (although it would bog again after a minute. Is there a vent for the gas tank? Do these carbs get vapor locked easily? I'm starting to reach for any idea...but, it's kind of fun anyway.

Dave