Starting After Carbs Rebuilt

[tahoe healey]

Are the fiber washers on top of the float chamber the vented ones? I know a stretch but you need to check everything.

 

[steveg]

Since it fires up reliably with starting fluid, I would guess that the problem is not a lack of spark.

DM - If you take off the float covers, domes and pistons - and you see gas in the float chambers - if you push down on the floats you should see gas overflowing out of the jets. If there's gas in the float chambers, there's enough gas for the car to run for at least a few seconds to a minute even if the fuel pump is not working (which it seems to be).

If you don't see gas rising out of the jets, maybe the passages between the float bowls and carb bottom are clogged.

My point about the spark is if there is fuel in the carbs per above, and if there is a spark, then the only reason it won't fire up is that the spark timing is so far off it can't run.

The cars will run on one carb - it's difficult to imagine the same exact problem with both carbs.

However it is easy to imagine an ignition problem keeping the car from running at all, as that affects the entire engine.

Edit: Tahoe makes an excellent point. If both the fiber washers (item 41) are incorrect solid washers, it could keep the carbs from functioning.

 

[red57]

While I generally follow the "what was the last thing you touched" approach to problem solving - which in this case is the carbs (and I still think following up with Apple would be good), Steve makes a good point in that it wouldn't be the first time someone was blindsided by a new issue happening out of the blue.

Forty years ago I was active in a small local fire department and I remember them harping on the idea that "Just because you are responding to a fire is no guarantee that there will be not another fire somewhere else in the neighborhood". We never took all our resources of equipment and personnel to one fire, just in case there was another one.

It will be interesting to hear the 'rest of the story' when you find the problem.

Dave

 

[Bill Young]

Have you found out why the engine will not run on the carburetors yet? Sounds like a this could lead to a Technical Service Bulletin article for the Healey Marque magazine. The BCF readers have suggested many tests to determine the problem.

Bill Young, Columnist
Healey Marque magazine
St. Johns Florida
sjahc.com

 

[Michael Oritt]

DM--

Unless I missed something you have still not verified that there is a good spark firing at the proper time, and you understandably assume that because the car ran on starting fluid ignition cannot be the culprit.

I have read that some starting fluids are susceptible to autoignition and will permit an engine to fire even without the presence of a spark. While I am not saying lack of spark is your issue you really should assume nothing and put the question to rest by pulling a plug and, while holding it next to the block, observing whether a spark jumps during cranking. As they say, 90% of fuel issuers are ignition-related.

 

[blueskies]

Starting fluid will make engines run that have issues. I don't like to use it on gas engines, but it has its place to get things running that won't start otherwise.

I managed to start a Healey 6 cylinder engine with four of the six plug wires connected to wrong cylinders. Only cylinders 1 and 6 were correctly wired. The mistake happened by thinking that the rotor rotated clockwise, not counterclockwise as it does in a Healey. The car did not run great, but it ran. It even drove on those two cylinders. What a difference when all six wires were hooked up properly.

 

[Editor_Reid]

Starting fluid will make engines run that have issues.

Just a brief sidebar, but I only recently became aware that an Australian nickname for starting fluid is "Start, ya bastard," as in, "I need a can of start, ya bastard!" I love it! Leave it to the Aussies!

 

[glemon]

I messed up the vents on my BN1 carbs when I rebuilt them. Not saying don't check it, but it had the effect of too much fuel not too little. There is air in the float chamber, if the air can't escape as it fills with gas the air pressure builds up, stops the flow of gas into the float chamber before it raises the float enough to close the valve, and gas literally shoots out the jet. A sight I won't soon forget.

Either gas isn't getting to the jet (I am having a hard time coming up with a theoretical why on that one based on everything described) or maybe a major vacuum leak that is preventing the air from me being enough to stop the fuel from being sucked up from the jets and into the cylinders. But I would think even with a leak it could run (though poorly) on gas after starting with the go juice. If a spouse or buddy cranks it and you put your hand over the carb throat does it suck? (Don't do this with starting fluid)

 

[steveg]

DM - any followup?

 

[blueskies]

Not saying that it could not happen, but a company that specializes in rebuilding SU or other carburetors should be able to set them up so that the car will run reasonably well, without tinkering, out of the box. One way to rule out the fuel delivery system upstream from the carburetors would be to hook up a temporary fuel supply - either by using a fuel line and electric pump from a gas can or by using gravity from an elevated fuel supply without a pump. Of course, when working with gasoline, safety is paramount; so make sure to understand how to do this safely. If the car still won't run, and if the spark is strong and at the right time, then there may well be a problem with the carburetors.

 

[Bill Young]

DM

Did you sort out the problem? It would be interesting to know what caused this unique situation.

Bill Young, Columnist
Healey Marque magazine

St. Johns Florida
sjahc.com