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TR2/3/3A TR3 Engine Miss Part 2

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oxendine

Jedi Hopeful
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Took some advice here ans soaked all the cylinder walls with sea foam (my Favorite). The compression on all cylinders is now between 125-150. Put the plugs back in, fired it up and the same results. The back 2 cylinders are not firing. Valves are adjusted, good spark. Not sure about the fuel delivery though. The rear float bowel has gas and does not seem to be sticking open or shut. I don't know what to check next. Any Ideas?

Thanks, Donnie
 
I think that you need to back flow some compressed air through the jet and into the float bowl. Remove the dash pot and piston, and the float bowl top. Blow air down through the jet. This should unstop and clear the line from the bowl to the carb jet. May also show what, if anything, was plugging it.

If this doesn't fix it, check the intake manifold for for blockage.
 
Marvin Gruber said:
You can have good spark to the plugs but that doesn't mean the plugs are firing. Put some new plugs in and see what happens
Click to expand...
Or if you don't have new plugs handy, swap them between the cylinders that run and the ones that don't. If the problem follows the plug, you know what it is.
 
TR3driver said:
Or if you don't have new plugs handy, swap them between the cylinders that run and the ones that don't. If the problem follows the plug, you know what it is.
Click to expand...

Did you use to work for IBM?
 
Nope, just a lot of years coaxing old, tired engines to run.
 
I could try swapping plugs but don't really think that will solve the problem. I've had the plugs out with wires attached laying against the block and saw a good spark at the electrode. I took the carb apart as noted in an earlier post and backed flushed it. Air cam through the jet into the float bowel fine. I'm planning on trying to get an old mechanic friend of mine here sometime this week to see if he can figure it out.
 
Sometimes old plugs will fire under atmospheric conditions, but not when air is compressed in the cylinder. This could be the fault of a weak coil not firing the plugs when installed.
 
bgbassplyr said:
Sometimes old plugs will fire under atmospheric conditions, but not when air is compressed in the cylinder. This could be the fault of a weak coil not firing the plugs when installed.
Click to expand...
What he said. Glazed plugs can also do the same thing, as the glazing becomes more conductive under compression (or being wet with fuel).

At any rate, it's an easy thing to try.

Since no one else has mentioned it, have you double-checked the firing order? Checked the plug wires for continuity/resistance?

To my way of thinking, it's not likely to be carburetion since the two rear cylinders appear to be doing different things (but are both fed from the same carb). But something like a stuck or burned valve in one cylinder can affect the other cylinder on the same carb, because the airflow is disturbed and reversion is increased.
 
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