Cars bogs after 45 mph.
 

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

Re: Cars bogs after 45 mph.
 

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.

Re: Cars bogs after 45 mph.
 

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.

Re: Cars bogs after 45 mph.
 

Condensor?
Coil?

Re: Cars bogs after 45 mph.
 

Thanks for suggestions.
Will try running without aircleaners, and check coil and condensor.
Thanks guys.
Bob

Re: Cars bogs after 45 mph.
 

another thought, is the muffler plugged, cars with plugged catalitic converters act the same way

Re: Cars bogs after 45 mph.
 

Ken,
Tried running without chrome cleaners.
Actually a little better but, still bogs.
Thanks for the info,

Bob

Re: Cars bogs after 45 mph.
 

Car does not have catalytic converter.
Good thought though ,

Thansk,
Bob

Re: Cars bogs after 45 mph.
 

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.

Re: Cars bogs after 45 mph.
 

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

Re: Cars bogs after 45 mph.
 

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.

Re: Cars bogs after 45 mph.
 

NO, Not Rudy.
Thanks for the advice on.043 in both. or 3.5 or 4.5 power valves.

Thanks,
Bob

Re: Cars bogs after 45 mph.
 

Ken,
Uncle Max rebuilt these carbs for me.
Really nice guy.

Bob

Re: Cars bogs after 45 mph.
 

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

Re: Cars bogs after 45 mph.
 

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.

Re: Cars bogs after 45 mph.
 

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

Re: Cars bogs after 45 mph.
 

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.

Re: Cars bogs after 45 mph.
 

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

Re: Cars bogs after 45 mph.
 

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.

Re: Cars bogs after 45 mph.
 

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!

Re: Cars bogs after 45 mph.
 

No need on stroms,all you have to do is install smaller PV in them. like #67 to #69. PV on Strom dont open till the pedal is on the floor.Not vac oper. ken ct.

Re: Cars bogs after 45 mph.
 

Russcc,
Thanks for input about dual accelertator pumps.

Ken,
Uncle MAx used .043 main jets and #69 power valves, he replied to me
in a PM.
Thanks,
Bob

Re: Cars bogs after 45 mph.
 

Ken,
Uncle Max told me that here is a lifetime warranty on the carbs he rebuilt for me, but
he also told me that he is a young 101 yrs. old.
Bob

Re: Cars bogs after 45 mph.
 

Start with the very basics. Retarded ignition timing will cause your car to bog under load. Make sure your points are set right as well.

Re: Cars bogs after 45 mph.
 

I think you have another problem,not carbs. MAX is the best,it dont get any better than him. ken ct.

Re: Cars bogs after 45 mph.
 

I found .043 in front carb and replaced with .045 to match rear...appears .043 is a better choice (your recommendation) in all 4 locations. H&H recommended these jets and you are correct I bought #65 PVs separately (and emulsion tubes) as well as recommended by others. (Appears #65=.035dia, #66=.033,#67=.032, #68=.031, #69=.0292) Never had the pedal to the floor to get into this circuit as a bit rough prior to that as I described.

How about changing the accelerator pump rod to summer from winter setting on the 97?

My setup has been in place since my Father owned the car in the 50's. No pump mods I am aware of and never ran a regulator- pump output is approx 5.5psi. The Internet has allowed me to make the regulator and jet "improvements". ;)

Re: Cars bogs after 45 mph.
 

Yes moving to S would probebly help,then you run into the rod being wrong length,there are 2 diff lengths.Thats another can of worms. Fulcrum arm must be bent to accomadate the shorter rod so throttles open and close fully. You put stock PV's in it. they also must be smaller like around #68. Its hard to believe your running with 5.5 lbs gas pressure. ken ct.

Re: Cars bogs after 45 mph.
 

Could be bouncing points (poor spring tension ) Bad connections ING side of coil .closed up points .bad coil .set up a jumper wire direct to coil .

Re: Cars bogs after 45 mph.
 

Ted,first thing they blame is the carbs when somethings wrong. ken ct.

Re: Cars bogs after 45 mph.
 

Yes Ken, If I rebuilt a Carb and the owner was not running a filter at the carb I would be reluctant to warrant it ,Some after market non Ford / AC ,pumps do not have enough clamping action on the cork seal to gorse

Re: Cars bogs after 45 mph.
 

You could go into the distributor repair business- double your revenue and quadruple your re-work requests! :eek:

I moved my Offy dial regulator to 3.5 psi (from 2.5psi) yesterday. (Dad didn't run one on this car- I added one)

Results were dramatic. The miss/crackle at "high" rpm (approx 2500-3000 by ear) was gone with engine at op temp. As the temp gauge moved up a bit after some idle downtown the miss began to appear- although much less pronounced. I was able to go full throttle in high gear for first time.

Apparently these regulators don't produce stated pressure at all operating temps/flows...The float shutoff valves are Strombergs latest- perhaps they are improved now for improved cutoff over the original design? The Sberg literature I have indicates 3psi max.

A search at this site indicates a 3039 NAPA paper fuel filter is recommended- I haven't tried one- some light sediment in my bowl. If that helps Bob.... Tank is "clean".

I will likely put the .043 jets I have in front carb and test drive again. Ran well enough that I could just leave it alone. If it improves a bit I'll purchase and match .043 jets for the rear. ( Fwiw this engine has "race" cam, .120 overbore, and Offy Hi rise with the twin 97s)

Lane

Re: Cars bogs after 45 mph.
 

yep, need a mechanical pressure gauge to check the setting....might find out you're not even putting out the 3.5...good luck....Mike

Re: Cars bogs after 45 mph.
 

Update on car bogging after 45 mph.
Turns out that I have a flat lobe on my camshaft,
affecting the rod which controls the mechanical fuel pump.
I am putting in an electric fuel pump to solve problem.
So, it defintely wasn't the carbs.
Thanks for everybody's input.
Bob

Re: Cars bogs after 45 mph.
 

Well im glad you found out it wasn't the carbs,way to go Max. Though i still think he should balance carbs with all .043 jets,OMO ken ct.