Free Shipping

800-946-2642
Shop by Car
   Forum Width:     Forum Type: 

Found 32 Messages

Previous Set of Pages 1 | 2

 Posted: Jun 20, 2017 11:12AM
Total posts: 7097
Last post: Jun 23, 2017
Member since:Aug 14, 2002
CA
When it runs for "5 seconds", how does the engine die? Does it stop firing abruptly, or does it gradually slow down in rpm until it stops? Slowing down and stopping suggests too much or too little fuel. An abrupt stopping of firing (like when you switch off an engine) suggests loss of ignition. Figure out which it is.

When it dies, remove a couple of spark plugs quickly and sniff them for gas (as in unburnt fuel). If they are dry it suggests an absence of fuel. If they are wet or smell like fuel, it suggests loss of spark and/or too much fuel = flooding.

You mentioned the bowl is more than 3/4 full with the top and float removed. That suggests a bad float or one that is set too high., or is sticking. The fuel level in the bowl corresponds (generally speaking) to the level of fuel in the main jet, where the carb sips gas. If it is too low, the carb has to work too hard to get fuel and the engine starves. If it is too high, the main jet can actually overflow, trickling raw fuel down into the intake system, and the engine floods. Once it floods, it won't fire until the cylinders and spark plugs are dry enough. That may take hours, unless you remove and dry all the plugs and crank the engine with the plugs out to expel the over-rich mixture and then put the plugs back to try again.
Another possible flooding situation is that the inlet jet needle, controlled by the float, is not sealing properly, allowing the fuel pump to push gas right through the bowl and main jet on into the intake manifold.

If the bowl is full but the tube connecting it to the bottom of the main jet is damaged, worn or dirty, you may get a slow trickle of fuel into the jet, enough to start the engine but not enough to keep it running... for a few seconds. Sound plausible?

.

"Hang on a minute lads....I've got a great idea."

 Posted: Jun 20, 2017 10:53AM
Total posts: 7097
Last post: Jun 23, 2017
Member since:Aug 14, 2002
CA
Image Gallery
DrewM: your photo is kind of distorted, possibly because you held the camera (phone?) too close. Try taking a picture farther back, like I did - attached are two photos of my old HS4.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Jun 20, 2017 09:29AM
 Edited:  Jun 20, 2017 09:33AM
Total posts: 82
Last post: Jun 20, 2017
Member since:Sep 20, 2012
Does this picture help? I hope it isn't too big. This angle suggests that the narrow part of the dashpot cover is a lot taller than it actually is.


 Posted: Jun 20, 2017 09:19AM
 Edited:  Jun 20, 2017 09:26AM
Total posts: 82
Last post: Jun 20, 2017
Member since:Sep 20, 2012
Quote:
Originally Posted by dklawson
I will try to post a picture below.  Unfortunately it is hosted on the MG Experience website.  Sometimes direct links to their pictures do not work.  The picture shows an HS2 next to an HS4.  You'll observe they look very similar but the vacuum chamber on the HS2 is much smaller in diameter.


How well did the engine run before you removed the head?  Really the carb and ignition settings should not have been disturbed when you replaced the head gasket.  I'm not sure we're looking at the right spot to find the problem.

As a quick test, the next time the car refuses to start, tip a thimble of gasoline down the carb throat and try to restart the engine.  If it bursts into life, runs briefly, then dies, you have a fuel delivery problem.  If the engine refuses to start, you either have a flooding condition or an ignition problem to sort.



It actually ran pretty well. I think I may have hit something while removing the intake? I remember that being a struggle.

Ok, I can try that.

 Posted: Jun 20, 2017 09:11AM
 Edited:  Jun 20, 2017 09:15AM
Total posts: 82
Last post: Jun 20, 2017
Member since:Sep 20, 2012
Quote:
Originally Posted by h_lankford


there are some inconsistencies in this thread that concern me . Sorry if this sounds conspiratorial, but......

compression went from low to normal: 

(1) by removing the adjuster nuts that felt "so tight they started to strip." How does one reassemble that? Stripped= not hold. 

(2) performed without asking for advice on cam lobe location and adjustment sequence, yet other questions suggested lots of help needed on simpler procedures.

(3) can someone explain to me how a head that was running fine (except for coolant leak) and had presumably normal valve adjustment, say .014", have that head removed, then replaced, and the valve lash on all four cylinders be not just a few thou but all way far off, thus lifting the valves off their seats and losing compression? A way too thick new head gasket, yes. Anything else? (I am excluding a warped head or heaped up around the studs since the compression figures are now reported normal and there is no coolant leak.) Someone may answer "it happens" but I'd like to hear more.









That's ok. My race car was an FI rotary. I'm almost completely self taught. I've picked up things here and there from friends and manuals, etc. Piston engines are rather new for me. I understand the basics but some of the details, ie which size needle to use in which carb, are things I still have yet to learn. There's no better engine to learn on than these cheap little small bore engines.

(no idea why that first part is quoted)
1 The outside of the nuts were becoming rounded. The threads were all fine. Heating them expanded the size and allowed me to loosen and correctly adjust them with little effort. I didn't think a heat gun would heat them enough because the one I had for cleaning loose rubber off the slicks didn't get very hot. I was pleasantly surprised to see that sears now carries a better heat gun that gets hot enough to melt your ice cream from across the room.

2 A friend did once show me how to do this on my previous mini. I also have the manual which lists the which valves to adjust and in which order. It's pretty simple, in my opinion.

3 I wish I knew. Only thing I can guess is that the new copper gasket was thinner than the old copper gasket I took off. Maybe a different manufacturer.

 Posted: Jun 20, 2017 09:06AM
Total posts: 8429
Last post: Jun 23, 2017
Member since:Jun 5, 2000
US
I will try to post a picture below.  Unfortunately it is hosted on the MG Experience website.  Sometimes direct links to their pictures do not work.  The picture shows an HS2 next to an HS4.  You'll observe they look very similar but the vacuum chamber on the HS2 is much smaller in diameter.


How well did the engine run before you removed the head?  Really the carb and ignition settings should not have been disturbed when you replaced the head gasket.  I'm not sure we're looking at the right spot to find the problem.

As a quick test, the next time the car refuses to start, tip a thimble of gasoline down the carb throat and try to restart the engine.  If it bursts into life, runs briefly, then dies, you have a fuel delivery problem.  If the engine refuses to start, you either have a flooding condition or an ignition problem to sort.

Doug L.
 Posted: Jun 20, 2017 08:45AM
Total posts: 82
Last post: Jun 20, 2017
Member since:Sep 20, 2012
Quote:
Originally Posted by dklawson

When you say it ran for 5 seconds and died, was it running when you released the key or only when you held the key in the start position?

You put a new coil on.  Which coil did you install?  What are the colors of the wires on each coil terminal?  Look carefully at the colors.  If one on the coil (+) terminal appears white, make sure it is not "off white" or "pink".  Let us know the coil wire colors.

Refresh my memory.  Which carb(s) do you have, HS series or HIF?  If HS carbs, do you have a single or dual carbs?

When you say the bowl is full, how full is it?  With HS carbs the bowl is to the side of the main carb body and you can inspect the fuel level by removing the 3 screws and taking the lid off.  The bowl should not be full, it should be about 1/2 to 2/3 full when there is no float taking up space.



It was running on its own, not off the starter. It'll crank and crank on the starter but it did fire and run this time. It was a quick flash of excitement!

I don't recall which coil it is. It's a new spare I had from another project that didn't come to fruition. I'd have to dig through receipts to find out for sure.

I believe the carb is an HS4. Though I will be honest I don't know how to tell the difference between the HS2 and HS4. I thankfully only have 1 carb to worry about.

The bowl is quite full. It was over 1/2 full though I didn't look to see exactly how full. I was just looking to see if there was any fuel in there.

I can take pictures if that makes it easier.

 Posted: Jun 20, 2017 04:57AM
Total posts: 1816
Last post: Jun 20, 2017
Member since:Aug 29, 2001


there are some inconsistencies in this thread that concern me . Sorry if this sounds conspiratorial, but......

compression went from low to normal: 

(1) by removing the adjuster nuts that felt "so tight they started to strip." How does one reassemble that? Stripped= not hold. 

(2) performed without asking for advice on cam lobe location and adjustment sequence, yet other questions suggested lots of help needed on simpler procedures.

(3) can someone explain to me how a head that was running fine (except for coolant leak) and had presumably normal valve adjustment, say .014", have that head removed, then replaced, and the valve lash on all four cylinders be not just a few thou but all way far off, thus lifting the valves off their seats and losing compression? A way too thick new head gasket, yes. Anything else? (I am excluding a warped head or heaped up around the studs since the compression figures are now reported normal and there is no coolant leak.) Someone may answer "it happens" but I'd like to hear more.

 Posted: Jun 19, 2017 12:52PM
Total posts: 8429
Last post: Jun 23, 2017
Member since:Jun 5, 2000
US
The quote function isn't working for me so...

From DrewM
"I replaced the coil because that was the easiest to do. Once again it ran for 5 seconds and died. No throttle response and it won't refire. The bowl is full.

Progress but back to where I started. Why the heck is the fuel not getting from the bowl to the cylinders? I cleaned the piston and needle assembly before. My next step is to clean the bowl assembly."

I am glad you got the compression back up.  That's a good start.

When you say it ran for 5 seconds and died, was it running when you released the key or only when you held the key in the start position?

You put a new coil on.  Which coil did you install?  What are the colors of the wires on each coil terminal?  Look carefully at the colors.  If one on the coil (+) terminal appears white, make sure it is not "off white" or "pink".  Let us know the coil wire colors.

Refresh my memory.  Which carb(s) do you have, HS series or HIF?  If HS carbs, do you have a single or dual carbs?

When you say the bowl is full, how full is it?  With HS carbs the bowl is to the side of the main carb body and you can inspect the fuel level by removing the 3 screws and taking the lid off.  The bowl should not be full, it should be about 1/2 to 2/3 full when there is no float taking up space.

Doug L.
 Posted: Jun 19, 2017 08:25AM
Total posts: 82
Last post: Jun 20, 2017
Member since:Sep 20, 2012
Ok, so I bought another heat gun and was able to adjust the valves. As we all suspected, that was the cause of the compression issue. It's now at 170, 170, 180, 180. 

No fire.

I replaced the coil because that was the easiest to do. Once again it ran for 5 seconds and died. No throttle response and it won't refire. The bowl is full.

Progress but back to where I started. Why the heck is the fuel not getting from the bowl to the cylinders? I cleaned the piston and needle assembly before. My next step is to clean the bowl assembly.

 Posted: Jun 17, 2017 05:24PM
Total posts: 8429
Last post: Jun 23, 2017
Member since:Jun 5, 2000
US
Failing breaking the adjusting nuts free by force you can try heat.  You can also get a replacement rocker assembly from another A-series engine.  In addition to Minis, you can get rocker assemblies from Sprites, Midgets, and Austin Americas.

Doug L.
 Posted: Jun 17, 2017 12:47PM
Total posts: 82
Last post: Jun 20, 2017
Member since:Sep 20, 2012
Ive tried it all. Theyre not going to budge.

 Posted: Jun 17, 2017 12:06PM
Total posts: 8429
Last post: Jun 23, 2017
Member since:Jun 5, 2000
US
Focus on torque and grip.  As I mentioned earlier, try a 6-point socket on a ratchet wrench.  Use a big wrench with a long handle.  Put an extension pipe on the handle if necessary.  They will break free.  

You cannot focus on carb or ignition adjustments until you resolve these low compression values.  Hopefully they are just from valves that are terribly out of adjustment.

Doug L.
 Posted: Jun 17, 2017 11:10AM
Total posts: 82
Last post: Jun 20, 2017
Member since:Sep 20, 2012
Doug, youve got to believe me. I went to adjust them again today and they're so freakin tight. They had to have been adjusted when they were hot. Theres no way to get them that tight when theyre cold without destroying them. Would a heat gun be able to heat them enough to loosen those nuts? Ill go buy a new one if it will.

I'd be ok with using a mild flame if necessary but only with the rocker assembly on the bench. 


If that doesn't work, yeah maybe a trip to the machine shop will be necessary. Im crossing my fingers I don't have to take it apart again.

 Posted: Jun 17, 2017 10:34AM
Total posts: 8429
Last post: Jun 23, 2017
Member since:Jun 5, 2000
US
60,100,80,60 ?

That sounds to me like the head is not fully seated or the valves are horribly out of adjustment.  Did you go back and adjust the valves?


Doug L.
 Posted: Jun 17, 2017 10:09AM
Total posts: 82
Last post: Jun 20, 2017
Member since:Sep 20, 2012
Quote:
Originally Posted by h_lankford
 Start with basics- please provide compression figures to be sure that new head gasket is doing its job. 


60,100,80,60

And now no spark. The plugs had fuel on them and so did the compression tester.

It was running before. I'm going backwards. (Sigh)

 Posted: Jun 9, 2017 10:44AM
Total posts: 82
Last post: Jun 20, 2017
Member since:Sep 20, 2012
again, i tasted it. it was coolant.

 Posted: Jun 8, 2017 06:36PM
Total posts: 8429
Last post: Jun 23, 2017
Member since:Jun 5, 2000
US
Quote:
Originally Posted by DrewM
I did taste the coolant on the ground. I didnt see any cracks in the head when I took it off.

When I went to set the valve lash, the retainer nuts that hold the adjuster screws were so tight that they started to strip. So I just left it. 
What did the liquid on the ground taste like?  Sweet = antifreeze.

Did you sniff or taste the liquid you saw coming out of the exhaust?  As above, sweet=antifreeze.  No strong taste= condensation.

When you change a cylinder head you cannot leave the rockers the way they were.  Sorry. Use a 6-point socket and ratchet wrench to loosen the adjusting nuts.  That won't round the corners.  When you re-tighten the nuts after setting the clearance, use a box end or combination wrench.  You can also use a flare nut wrench to tighten the nuts as they are typically 6-point which makes it unlikely they will slip.

Doug L.
 Posted: Jun 8, 2017 03:59PM
Total posts: 82
Last post: Jun 20, 2017
Member since:Sep 20, 2012
I did taste the coolant on the ground. I didnt see any cracks in the head when I took it off.

When I went to set the valve lash, the retainer nuts that hold the adjuster screws were so tight that they started to strip. So I just left it. Someone obviously ran into this problem before too. Theyre all beat up. If i loosen the whole rocker assembly, will those nuts loosen?

 Posted: Jun 8, 2017 03:32PM
Total posts: 1816
Last post: Jun 20, 2017
Member since:Aug 29, 2001
ASSUMING your correction of the gasket solved the intake system leak, then there is a second problem. 

If it ran well before you disassembled the carb, but not now, then maybe you should retrace those steps. 

I would pull all the plugs, check compression at all four cylinders, and be sure that valve lash is set right. If indeed coolant was coming out the tailpipe ( did you taste it?) then a warped head or cracked head are posdibilities. All this is speculation. Start with basics- please provide compression figures to be sure that new head gasket is doing its job. 

Found 32 Messages

Previous Set of Pages 1 | 2