Fuel Percolation and Fuel Stabilizer

496BBC

Well-known member
Joined
May 13, 2008
Messages
210
Location
Deep in the marsh, South Louisiana
Whats the possibility that fuel stabilizer helps with carb fuel percolation?

I've had an ongoing issue with carb percolation around 20 to 30 minutes after shutting the engine down on start up.

I've worked on it and have it about as good as I've been able to get it until now.

I've insulated the fuel lines, connected the return line and added a heat shield under the carb. all of this has helped allot but I still have the the issue with percolation.

I recently added some Marvel Mystery Oil to the gas, with winter coming I'll be driving it less for a few months.

I've noticed that the last few times I've driven it I haven't had the hard start issue and the only change I've made has been the addition of the MMO to the gas.

Now I've not driven it enough to really put this to the test and it is starting to cool off here so I can't say for sure that the fuel stabilizer is whats doing it but I'll be watching closer to see if my hard start issue goes away.

I'm going to do some research on fuel stabilizers to see how they work to see if there is some correlation there.

Anyone here that can maybe shed some light on this theory?

Neal :idea:
 
I know nothing of fuel stabilizers, but years ago found that electric chokes and pouring Plaster of Paris into the crossover passage under the carb....very long term success with blocking off heat....obviously the heat riser valve on pass side need eliminated.....

end of ALL fuel perk/hot carb/boiling/problems....:yahoo::goodnight:
 
When I get my '79 out after it's been sitting for a few days I always use starter fluid spray ... no problems, starts everytime...

Now, when I drive it for a while, park and then try to re-start after it's been sitting for 30 minutes or so.... it will take a bit of cranking and a few pumps on the right pedal....

I've used MMO in the fuel but not sure there was a noticeable difference...
 
I use 1 thin stainless heatshield between 2 gaskets, fuel return, and the crossover blocked in the manifold.

Always starts at the click of the starter when hot. Only problem is this ethanol evaporation after a week of sitting.

As far as the stabilizer, Stihl sabilizer has a boiling point of over double that of e10 and a vapor point of over double, so yes the stabilizer should help a bit in perculation.

Someone has claimed that the big turkey pan heatshields have reduced carb temps by 50° along with air flow over the engine and out of the compartment.
 
The only thing I have found on how the stabilizers work is they encapsulate the carbon molecules so they don't interact with the oxygen molecules to prevent oxidation leading to degradation of the fuel.

I have added a Holley heat shield and have removed my fresh air pan from the carb to allow air flow up and over the carb and out the scoop when shutdown, I also removed my aluminum 1" carb spacer and replaced it with a phenolic spacer.

All the changes have helped but it seems that the addition of MMO has stopped it completely. Its still to early to say that its over for good but I'm hopeful.

Neal
 
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Oh oh ooo ooooo!!!! I know the answer to this one! I fought this crap for two years before I realized what was happening, and I did not know how to ask the right question, anyway.

You have done good so far, but add a phenolic spacer under carb, Kiss your troubles good bye! I managed to get a 1 inch under mine. A friend gave me a holley heat shield with a 1/2 inch spacer(not phenolic but should work as well. Two gaskets just is not enough, tried that too. Send me a stamp and I'll pass on the love to you. PM me with your address and it's yours.

tt
 
Well poop, my old eyes missed the spacer part, sorry. Yes, you should be good with all you have done. Tough down here in the south around June / July for sure !

Good luck!

tt
 
i've been wanting to put a phenolic spacer between my holley and the intake manifold.
the problem is how do i get the studs out of the alu intake manifold without breaking it?
thanks
:cool:
 
i've been wanting to put a phenolic spacer between my holley and the intake manifold.
the problem is how do i get the studs out of the alu intake manifold without breaking it?
thanks
:cool:

Get the entire assy soaked in some penetrating oil....I typically use WD40 other guys like other stuffs....let soak for a day or so....

heat the thing up but GOOD, really hot....

if you CAN, get some dry ice, if not....maybe just freezer ice cube....

stick the ice on end of the stud, hear that hiss/CLICK?? when it clicks, get your vice grip on that dawg...in a HURRY....out it comes....

you got the steel to shrink and the aluminum is still hot....the corrosion let go, and so spin it out.....HOPEFULLY.....I done more than a few times, never failed....

:flash:
 
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