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TR6 Black sooty plugs continue - What now?

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Thanks Larry -
I'm near Tulsa Ok and have been working with our Club mechanic.
UPDATE: after adjusting both carbs way-way lean - it ran great & plugs ALL cleaned up!

Now today: missing at 3ooo rpm & up then stumbing miss at lower rpm & idle. replaced fuel filter, checked timing & dwell --no help.... plugs still look great!
 
Every suggestion in this thread is directed to your carbs being the issue ! Have you checked the strength of each of the 6 sparks.
 
busybrit
Thanks for the reply- I have not had an instrument to check spark strength,but I think it would be very interesting info.
Last week we got the plugs & missing to clear up adjusting both carbs very lean.
Now it's developed a different miss: at 3000/4000 rpm when accelerator is floored - a staccato miss then after some driving it has
a stumbling type miss that gets worse even at low speed and idle.
It sounds like fuel/air issue now.
 
Check the diaphragms that surround the top of the air valve..not only for holes and slits but also for proper orientation so that the 2 holes in the perimeter of the bottom of the air valve are pointing to the center of the intake manifold's port.
 
tv44engr said:
I have never used ethanol gas.
Click to expand...

I find that surprising. For emissions purposes, all the gas around here contains some percentage of ethanol. It has been that way for several years now since MTBE was removed from fuel. I always assumed it was that way in the rest of the country.
 
dklaw

I'm also in NC but down near the coast. Ethanol free 89 octane is easy to find since a lot of boaters use it.
 
Perhaps the use of ethanol here is limited to high-density areas like Charlotte, The Triad, and The Triangle. It's pretty standard here for gas to have 10% ethanol with some pumps including a warning that they may have up to 15%.

Perhaps marine fuel is also subject to different regulations than cars.
 
I've seen ethanol free pumps increase in numbers...they aren't everywhere yet, though.
I used it for a while but since it was only in 87 octane, I eventually went back to mid grade with 10% ethanol.
My engine likes that.
 
dklawson said:
I find that surprising. For emissions purposes, all the gas around here contains some percentage of ethanol. It has been that way for several years now since MTBE was removed from fuel. I always assumed it was that way in the rest of the country.
Click to expand...

The local Southern States co-op here only carries ethanol-free in all grades. I usually use it for the lawn tractor and weed eater but for a while I used it in my daily driver when the differential cost wasn't that great. I got slightly better gas mileage but it was a wash in terms of the extra cost.

Scott
 
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