Engine Stumbles

[DS1980]

Hello folks,
First post here. I am a transplant from the minimania forum. I really enjoy working on, learning about, and talking about my 1972 mini. What I didn't like is the absurdity that the minimania forum has become. I'm sure there are a few present here that can verify.
As stated, I have a 1972 mini 850cc that is bone stock. I bought it in England in 2008 and brought it back with me. It was in Vegas until 2011 and then brought it over to Denver, Colorado. It ran like a top in England, like a top in Vegas, and ran like a top over here until one odd day it just started sputtering. The symptoms have been consistent and irritating.
The Symptoms:
The car will start just fine, warm up just fine and drive just fine until it simply begins to sputter and then dies. Sometimes I can catch it, push in the clutch and keep the revs up to "clear it out." It will run ok for a few moments and then starts all over.

What I've done:
Flushed the fuel system, rebuilt the carb, replaced the points, new fuel pump, checked the float boat level. Good oil pressure. I have felt the coil when this happens and it is not hot to the touch.
I have disconnected the fuel line at the carb and cranked the engine, good fuel flow. Has an inline fuel filter right before the pump.
I really think it's a fuel issue, but I am at odds what it can be. The carb is getting fuel. I have not really done anything with the ignition except check the coil and replace the points.

I'm out of ideas.

Darin

[94touring]

Glad you found your way over  4.gif

Engine ground wire clean?  Replaced the fuel filter?  Condenser?

[MiniDave]

Which carb does it have?

I second the notion of the condensor, and for not much money I'd change the coil too - I know a number of people who cured poor running with a new coil.

I'm sure you've also checked your valve clearances and double checked compression?

Always start with the basics first when troubleshooting - valve clearance, compression, then spark and then fuel.

I've found a lot of engine issues that turned out to be compression related - valves tight, burned and so on. None of the fuel or spark adjustments will fix a poor compression reading!

Report back with your results and we'll help you winnow it down.

[DS1980]

I will check the ground wire. Fuel filter is new.

I have a spare coil, I will throw it on and see if it works. May have a spare condenser paying around. If not:

http://www.minimania.com/part/C1-DCB101/Condenser-23d---25d-Pre74mini-Sprite--Midget   Correct one?

Haven't done anything with the valves or compression. Is the Haynes manual correct when it comes to valve clearances?

[DS1980]

Oh has the standard 850 carb. Can't remember the type. HS2 I believe.

[MiniDave]

My old 62 Cooper S used to run like shite when warm when the points closed up - I know you said you installed new points so I assume you're comfortable that you have them gapped correctly?

[94touring]

I know my distributor problem that was intermittent caused me to convert to an electronic unit. 

[towjoe]

I would second the condensor.
Regards
Joe 77.gif

[MPlayle]

It may also be altitude related.  I forget which way the altitude changes the fuel mixture.  I think it is the higher altitude causes the carb to run rich due to less air density.  Does pulling out the choke make it worse or better?  Worse, would fit with the carb running rich.  Better would be carb running leaner.  From there I would try adjusting your carb appropriately.  You may also have to take the dashpot off and see what needle you currently have and use some of the online resources to find the next one richer or leaner.

[94touring]

The fuel would be richer at altitude.  I wouldn't think more than a turn or two on the carb to make up the difference but certainly a possibility as well. 

[DS1980]

It may also be altitude related.  I forget which way the altitude changes the fuel mixture.  I think it is the higher altitude causes the carb to run rich due to less air density.  Does pulling out the choke make it worse or better?  Worse, would fit with the carb running rich.  Better would be carb running leaner.  From there I would try adjusting your carb appropriately.  You may also have to take the dashpot off and see what needle you currently have and use some of the online resources to find the next one richer or leaner.

I have seen high altitude mini owners with the same problems I'm having. We will lean it all the way out and the engine will still increase RPM when the piston is pushed up, indicating it is still rich. Pulling the choke when it's warm makes it worse. A few folks are saying condenser. Maybe I've misdiagnosed it as a fuel issue.

I'm going to open the dizzy back up, change condenser, recheck gap, and change out the coil.

[MiniDave]

After re-reading your description it does not sound like a fuel problem to me....I think you're on the right path....don't forget to check your timing after re-gapping the points.

After you get the electrical all sorted, then go to tuning the carb last. If you can't get it lean enough you may need a different needle. SU has charts online that will guide you in the selection, and 7 Ent and MM both have a selection of needles you can buy. Also, while you have it apart, make sure the piston slides smoothly in the bore of the dome....temp changes can cause a piston to stick if there's dirt inside the dome....then it will not run right.

You DID set your valve clearances and checked compression - right?

[DS1980]

Haven't done anything to the valves or compression. I do have a Haynes manual. Are the clearances in the manual correct?
I didn't have a condenser so it's in the mail. I went ahead and got a low tension lead as well. Will be a few days before I can get them replaced.

What is 7 Ent?

[94touring]

7ent.com sells parts.  State side I use gbcarparts or 7ent.

[John Gervais]

http://www.7ent.com/

Some of us have the needle books and application data from Berlen Fuel Systems; let me put my reading glasses on...

1972 850cc  Hmmmm...  I'll take a guess that you've got a fixed needle HS2 carb, so the 'EB' needle is std., 'M' will be your rich needle, and 'GG' will be your lean needle.

[MiniDave]

Hey John, could you look up one for me too?

Sea level, 1275 bored 60 over, std compression, mild cam, LCB header and running an HIF44.

[John Gervais]

Sorry Dave, wish I could help, it's hardly stock, therefore not in Berlen's little blue book. 

Not in Vizard's recommendations in HTMYM or TBLASE either, sure wish my WinSU worked with the newer versions of Windows.  I'm sure you could find it, though, on TMF or the old 'Ask Doddy' board.

[towjoe]

Hi Mini Dave,
I would try AC Dodd . Give him all your info on engine ,carb and cam. He did a grest job on needle profile for my engine.

http://www.minifinity.com/forum/index.php?sid=66902e602353aad4fee9ceae1747c29c
Regards
Joe    77.gif

AKA towjoe

[DS1980]

Wow, GG needle is scarce. Would like to try it though.

http://www.ebay.com/itm/1-1-8-1-125-H1-SU-CARB-CARBURETTOR-NEEDLE-GG-MORRIS-MINOR-SERIES-2-803-cc-NEW-/201424846534?hash=item2ee5db3ec6

Correct?

[MiniDave]

7Ent lists a GG, you might call them....

MiniMania also has them....

[MiniDave]

Hi Mini Dave,
I would try AC Dodd . Give him all your info on engine ,carb and cam. He did a grest job on needle profile for my engine.

http://www.minifinity.com/forum/index.php?sid=66902e602353aad4fee9ceae1747c29c
Regards
Joe    77.gif

AKA towjoe

Thanks Joe, I have to join up to ask him anything.....

[DS1980]

MM says out of stock.
I can't find it on 7ent.
Was that the correct needle on ebay?

[John Gervais]

GG = p/n AUD1211

[towjoe]

AUD 1211

http://www.minispares.com/image.axd?type=product&picture=350/AUD1211.jpg

Regards
Joe

[John Gervais]

or http://www.minispares.com/product/Classic/Fuel/Carburetors/Needles/AUD1211.aspx?130206&ReturnUrl=/search/classic/aud 1211.aspx|Back to search