stromberg larg logo 97's

[jan bogert]

i got two large logo 97's which way leans them out? I have them set since last year with a unisyn. today I changed my plugs, and they are black/sooty. the screws are only out about ONE turn. fuel reg. set at two and a half. exhaust tail pipe black/sooty

[tallrick]

turn in to lean it out, turn out to richen the mixture.

[lonewolf]

the screws are for your idle a/f mixture. you may have to lower ypur jet size for the main circuit

[Mike in AZ]

got a pressure gauge to check presssure from the regulator??....if you screw in the idle mixture screw, does the engine lose rpm's?....Mike

[uncle max]

Jan, I looked in my logbook and found that I sent your two carbs with .043" main jets and #69 powervalves...
This has nearly always been the combination that makes most small to mid size flatheads happy.
With this stuff they call gas today, my theory might be subject to change.
Check your fuel pressure, because if it's too high, your carbs will think they have larger jets!
If need be, PM me with your address and I'll send more jets. Free.

[1952henry]

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Originally Posted by uncle max

Jan, I looked in my logbook and found that I sent your two carbs with .043" main jets and #69 powervalves...
This has nearly always been the combination that makes most small to mid size flatheads happy.
With this stuff they call gas today, my theory might be subject to change.
Check your fuel pressure, because if it's too high, your carbs will think they have larger jets!
If need be, PM me with your address and I'll send more jets. Free.

Can't beat that with a stick. Pretty sure Speedway won't do that with their "97" knockoffs.

[jan bogert]

Max, I had been running it at 2 3/4, then went down to 2 1/2. i'll pm you with my address. thanks Max. 52 Henry, I don't want to ever hear speedway again. I experienced there super 97's I went back and forth with them. uncle Max, did me a good deal with these 97's, and I do know that you can't just get a pair bolt them on an things will be perfect. always will need a little adjustment.

[JM 35 Sedan]

Jan, if you are running air cleaners/filters, make sure they are not too restrictive.

[uncle max]

Very good point!

Originally Posted by JM 35 Sedan

Jan, if you are running air cleaners/filters, make sure they are not too restrictive.

[Mike51Merc]

Originally Posted by JM 35 Sedan

Jan, if you are running air cleaners/filters, make sure they are not too restrictive.

Agreed. I had a sooty plug problem that turned out to be a choke plate that wasn't opening 100%. You'd be surprised what a big difference a little restriction can make.

Try this to read your plugs: Take a cruise, warm up the engine, get on a nice straight road section. Go wide open throttle for a short distance, kill the engine with the ignition key, coast to a stop. Read plugs.

[keith oh]

This is just a comment, but judging from all the things Uncle Max does for all his customers including me, why would anybody buy anything to do with Strombergs from anywhere else?

[gkgeiger]

Originally Posted by keith oh

this is just a comment, but judging from all the things uncle max does for all his customers including me, why would anybody buy anything to do with strombergs from anywhere else?

++1

[Ross6860]

Originally Posted by Mike51Merc

Agreed. I had a sooty plug problem that turned out to be a choke plate that wasn't opening 100%. You'd be surprised what a big difference a little restriction can make.

Try this to read your plugs: Take a cruise, warm up the engine, get on a nice straight road section. Go wide open throttle for a short distance, kill the engine with the ignition key, coast to a stop. Read plugs.

You mean you don't need a chassis dyno, an A/F meter, and a computer?

+1 for old school

Another old tip. Get a stopwatch and use that same long straight section of road (a slight uphill is even better). Get a baseline time from say 40 to 60 mph in top gear (or from road sign to road sign, whatever you want to use). When you make an "improvement", you can check it.

I know, you need to compensate for air temp, barometric pressure, humidity, etc., etc., but this will keep you out of trouble (plus reading the plugs).

[Mike in AZ]

maybe bump down the pressure another half pound??...Mike

[jimalabam]

Re. Uncle Max - When you can deal with the best, why fool around with the rest ???

[Terry,OH]

Put a vacuum gauge on the engine and when warm adjust the four "IDLE adjustment" screws to get the highest vacuum reading and at the same time smoothest IDLE. For two 97's the final should be ABOUT 2 to 2-1/2 turns out on each screw. This will not cure soot covered plugs. Your going to have to change the main jets and a small change here will make a big difference. Usually one to two sizes smaller. It is better for the engine to run slightly rich than lean. To sync the two carbs together use your Uni-Syn and just adjust the IDLE RPM adjustment so the front and rear carbs match.