Cars bogs after 45 mph.

Displayman

Displayman

Senior Member
We have a stoxck 1947 Mercury, with a Fenton intake and dual stromberg 97's. Carbs have been rebuilt recently. Carbs have been balanced with the Unisys system. Both carbs have been COlor tuned with Gunson's Color
tune. Car was running great. Now it starts bogging when we go over 45 mph. I check fuel filter, fuel regulator is set for 2 1/2, sparkplugs are clean and gapped at .25.
It seems to get worse with the heat. We have been having 95 degree weather lately.
First and second gear runs smoothly, 3 rd runs smooth until 45 mph.
Any suggestions would be appreciated. Something that I am overlooking?

Thanks,
Bob- Hampshire, Illinois
 
Do you have the adjustable pressure regulator( dial type)? If so I have had problems with them. Try adjusting the pressure up to 3 1/2 pounds. If that doesn't help then remove it and see how the car performs.
 
If your running a pair of those small chrome Chineeze air cleaners ,try running them with/out the filter elememt in them.There was a problem with them a while back as being tooo restrictive. Worth a try if you have them on there. ken ct. A no cost try.
 
Thanks for suggestions.
Will try running without aircleaners, and check coil and condensor.
Thanks guys.
Bob
 
Ken,
Tried running without chrome cleaners.
Actually a little better but, still bogs.
Thanks for the info,

Bob
 
Im thinking M Jets too big.I would say around .043 would be about right. Whats in them,hope your not trying to run a progressive type linkage on there. ?? ken ct. And smaller PV's like #66 -67. ken ct.
 
Ken,
Defintely not running progressive linkage.
Carb was rebuilt by the one of the carb expert here(101 yrs old)
Forgot his name alreday, getting senile. lol
I believe he put in .46 or .48? I really don't remember
 
Displayman said:
Ken,
Defintely not running progressive linkage.
Carb was rebuilt by the one of the carb expert here(101 yrs old)
Forgot his name alreday, getting senile. lol
I believe he put in .46 or .48? I really don't remember
Click to expand...
I would go to .043 in both,and 3.5 or 4.5 power valves. Your bog could be from stock PV's especially if 7.5. Your getting a rush of so much gas the engine stumbles on it too much gas all at once. ken ct. Also would loose the rubber accel pumps if in there.If your thinking rudy faultiermier,no comment. Also rubber tipped inlet needles. SORRY THIS POST WAS TOTALLY WRONG<I HAD ( FORD CARBS ON THE MIND> LOL ken ct/ senior moment.
 
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D'man,
If uncle Max rebuilt your Strombergs I'd be surprised, no
shocked, if yours is a carb problem. As you say Max is a good guy...
email him direct.
Charlie ny
 
Is the engine loading up with gas ? If so, did Uncle Max know you were running them as duals when he did them ? If not read Barney Navarro's article, "The problems of dual carburetion", Rod & Custom, April 1954. Too much gas can be as result of 2 accelerator pumps, when only one is needed. The cure is simple, and in the article.
 
Displayman said:
Ken,
Uncle Max rebuilt these carbs for me.
Really nice guy.

Bob
Click to expand...
I would email him also he knows stroms as well as i or more so,im sure he will straighten them out ,hes a great guy to deal with. My hats off to him and his rebuilding. It may not even BE a carb problem.ken ct. Give him my best. He dosen't hear too well on phone. email.lol
 
I still think it is the adjustable pressure regulator. I've had more than one problem with them. A friend also took his off due to not getting the proper amount of fuel through it.
 
I've got a similar issue with my 59A with twin 97's which I rebuilt myself before discovering the coil brush was burned away and replacing coil, condensor, points etc. I installed the Offy regulator and set at 2.5psi and verified that pressure at idle.
Mine breaks up in 1st and 2nd as well at "high" rpms.

Thanks for suggestion for 3.5 psi..TJ..I'll post what I find to see if that helps Bob (don't mean to stomp on his thread for my first post :) ).
I've got .045s in both carbs, but found .043's in the front carb. Not sure what the PV's are...(whatever the standard Sberg kit comes with)...
I'm at sea level..fwiw

Lane
 
3.5 lbs pressure is at the limit a strom will tolerate.2-2 1/2 in more like it.How can you be running .045 in both carbs and then say you have .043 in the front one???? Should be .043 in both carbs. And power valves do NOT come in any kits that i know of. Except in OLD Sorensen kits. Stock PV's usually are too big running a 2x2. most run #67-#68 in them. Your running too much gas through them your over carbed. OMO ken ct.
 
If the accelerator pumps have not been modified for dual carb use, that is where I would look. The article by Barney Navarro shows how you drill a small hole in the pump setup to keep the gas level lower in the pumps so they don't give the engine to much gas. Think about it, the gas from 2 accelerator pumps when the engine originally only had pone. Too much!
 
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