221 37 issue

[Tinker]

so I’m fighting a 221 37 issue. Thinking it a vacuum issue personally but inquiring opinions.

run down:

ford barn approved:

Rebuilt engine:

compression solid at 100 across the board.

Ignition:

skip coil and ih200

bubba dizzy

Autolite 386 (18mm) plugs.

fuel:

new britt stromberg 97, fuel pressure 2-3psi.

Condition:

Great power at high rev, drop out/ hesitation at low revs or speeds or low lugs.


Everything points to low vacuum. I am able to completely turn in my 97 idle screws with no hesitation making me think vacuum, i have yet to put a vacuum gauge to the motor due to a place to do so. but... could this also be a valve issue. I have yet to set valves after there rebuild. Adjustable valves.


looking for opinions.

[Brian]

Vacuum brake screwed too far in?

[Tinker]

I've had good success with the brake in more then not.

Ive covered most ignition issues just more focused on the fact the idle screws do nothing.

[Phil Gillespie]

Tee off at vaccum line to wipers for a vaccum gauge to assist with your fault finding.
Vaccum gauge in my opinion is an item to be fitted to these engines as a matter of course. Gives you a path to follow without the guess work.
all the best with your problem
Phil NZ

[Terry,OH]

Remove the wiper hose (A leak in the hose or wiper can not effect readings on gauge) and place vacuum gauge on the manifold post for the wipers. It will tell you a lot, notice iF vacuum is steady and at what level or if it varies how much and to what levels and how fast.

[rotorwrench]

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Changing the opening of the idle mixture ports should have an effect. If you screw them all the way in to closed off position, the engine should quit running with throttle at idle. If not, I'd think there is another fuel source due to a leak in the carb somewhere. Float valve not shutting off, leak around power valve body, or leak from some other source inside there. Most new carbs should be ready to run right out of the box but you just never know now days.

[Tinker]

Originally Posted by rotorwrench

Changing the opening of the idle mixture ports should have an effect. If you screw them all the way in to closed off position, the engine should quit running with throttle at idle. If not, I'd think there is another fuel source due to a leak in the carb somewhere. Float valve not shutting off, leak around power valve body, or leak from some other source inside there. Most new carbs should be ready to run right out of the box but you just never know now days.

I agree, its seems to be running rich. Just want to rule out everything else since this is the second carb I've put on. Rebuilt 97 and now a New 97.

[Tinker]

I was able to get a vacuum gauge on the engine.

18" rock steady, no fluttering. When you pump the gas it drops around 5-8" and goes right back to 18".

Would anything else, other then the carburetor, that could be causing the idle screws to be screwed in and not totally stop the motor? It does slow it considerably. I just have a hard time thinking a fordbarn approved rebuilt 97 and a brand new 97 would be faulty?

Test drive today, starts quick. Idles well and gassing it without load is fine.

When I put it in gear and drive it starts to buck and a slight pop (after-fire). Pulling the choke halfway out, does help. But it still has some hesitation.

[JSeery]

Pulling the choke rod out should make it run richer.

[Lawrie]

CHeck the dissy,my 33 got a small miss ,would run great,but when I slowed and got off the gas the miss came ,
Turned out to be the points plate and advance unit had a lot of play and the points plate was loose in its bore in the housing,My mistake was setting the points with out tightening the timing adjust screw,so when I did this the plat moved in the housing and the points gap was all over the place,
lawrie

[Tinker]

Originally Posted by JSeery

Pulling the choke rod out should make it run richer.

That's partly what confounds me about it.

Originally Posted by Lawrie

CHeck the dissy,my 33 got a small miss ,would run great,but when I slowed and got off the gas the miss came ,
Turned out to be the points plate and advance unit had a lot of play and the points plate was loose in its bore in the housing,My mistake was setting the points with out tightening the timing adjust screw,so when I did this the plat moved in the housing and the points gap was all over the place,
lawrie

I had another dizzy from bubba that I had for backup and put that on. I also replaced the condensor with a IH200. Lastly I lowered the fuel pressure to around 2-2.5 from 3.5-4. New plugs also. It runs better but still getting the large hesitation.

Ignored my rule of change one thing at a time.

[JSeery]

A mid-range hesitation would normally indicate a power valve issue, but you have changed carbs, so?

[FlatheadTed]

Screwing them in shouldn't stop the motor as it feeds around the plate, I vote dirt in the idle jets or to small ,also look at the spray tubes ,check the winter and summer setting, Could be a hair line crack in the manifold ? Ted

[FlatheadTed]

Should be a full spray from both tube s .As far as I know The power valve doesn't come into play on a 97 until the leather plunger is fully depressed ,I think about 70MPH before that it get a richer shot from the two tubes ,but I have been wrong before, Ted

[drolston]

There is both an upper and lower discharge hole in the idle circuit of the 97. Screwing the idle adjustment screw affects only the lower discharge hole. The main jets can also contribute some fuel flow at idle. The engine may or may not stall if you close both idle jets. Depends somewhat on idle RPM. If you idle slow, like 500 RPM, it should stall with the idle jets closed. If you idle at 700 RPM, it may not stall.

I am assuming you have checked proper flow from the accelerator pump. If so, hesitation and pop-back still sounds like a vacuum leak. Put a pair of pliers on the wiper vacuum line to see if pinching that hose closed affects idle RPM. Check to be sure the vacuum fitting to the distributer is snug and not cross threaded. Next, use some spray starting fluid or carb cleaner. If you hit the leak source with that stuff, the idle speed will come up for a moment. New carb, but spray around the throttle shaft ends and mounting gasket, just to be sure. Then around the vacuum fitting to wipers and distributor. Then around the intake manifold surface and around the base. If that does not locate the leak, the manifold may have to come off to see if the leak is on the valve galley side of the manifold gasket.

Good luck.

[FlatheadTed]

Yes your right depending on RPM ,What about trying your hand half over the inlet to richen the mixture then rap the throttle ,

[Lawrie]

These pesky miss fires can be hard to track.
Once before my 33 had a miss,took me a couple of years to get on top of it,It would run allday at any speed towing,no drama,up hills and on the flat.lift off for road works or intersections,and on acceleration would miss fire ,the longer the deceleration period the longer it took to clean out,
turned out to be worn inlet guides sucking up the oil and fouling the plugs,
fitted new straight valves and guides and that fixed it.
Lawrie

[jimTN]

Does your intake match the carb. gasket and carb? If I remember right some of the later 221 intakes had a round hole to the rear that opened into the heat riser area, a mix up with the gasket and so on could cause a problem.

[G.M.]

It could be sticky valves. After it warms up drop to 8 or 10 MPH in high gear.
Push on the gas pedal gently and see how it pulls up in speed. If it bucks
drizzle some MMO down both side of the carb for about 30 seconds keeping
it running. Put about 1/2 quart in the gas tank and drive about 10 or 15
miles and try the slow down in high gear test again. If it's sticky valves it
usually go's away but you need a pint of MMO in every tank of fuel or it will
return. There is a thin white film of a resin like material that forms on the
valve stems. G.M

[Tinker]

Originally Posted by drolston

There is both an upper and lower discharge hole in the idle circuit of the 97. Screwing the idle adjustment screw affects only the lower discharge hole. The main jets can also contribute some fuel flow at idle. The engine may or may not stall if you close both idle jets. Depends somewhat on idle RPM. If you idle slow, like 500 RPM, it should stall with the idle jets closed. If you idle at 700 RPM, it may not stall.

I am assuming you have checked proper flow from the accelerator pump. If so, hesitation and pop-back still sounds like a vacuum leak. Put a pair of pliers on the wiper vacuum line to see if pinching that hose closed affects idle RPM. Check to be sure the vacuum fitting to the distributer is snug and not cross threaded. Next, use some spray starting fluid or carb cleaner. If you hit the leak source with that stuff, the idle speed will come up for a moment. New carb, but spray around the throttle shaft ends and mounting gasket, just to be sure. Then around the vacuum fitting to wipers and distributor. Then around the intake manifold surface and around the base. If that does not locate the leak, the manifold may have to come off to see if the leak is on the valve galley side of the manifold gasket.

Good luck.

I'll give this a shot. thank you.

Originally Posted by Lawrie

These pesky miss fires can be hard to track.
Once before my 33 had a miss,took me a couple of years to get on top of it,It would run allday at any speed towing,no drama,up hills and on the flat.lift off for road works or intersections,and on acceleration would miss fire ,the longer the deceleration period the longer it took to clean out,
turned out to be worn inlet guides sucking up the oil and fouling the plugs,
fitted new straight valves and guides and that fixed it.
Lawrie

Geez I hope it's not guides. The engine is a older (4-5 yrs) rebuild with very little miles (500 miles).

Originally Posted by G.M.

It could be sticky valves. After it warms up drop to 8 or 10 MPH in high gear.
Push on the gas pedal gently and see how it pulls up in speed. If it bucks
drizzle some MMO down both side of the carb for about 30 seconds keeping
it running. Put about 1/2 quart in the gas tank and drive about 10 or 15
miles and try the slow down in high gear test again. If it's sticky valves it
usually go's away but you need a pint of MMO in every tank of fuel or it will
return. There is a thin white film of a resin like material that forms on the
valve stems. G.M

It does buck in high gear at low speeds, really anytime its near a "lugging" condition (hills, etc). Also when starting out or whenever the motor drops down to a lower rpm (gear change). If the motor is running a decent rpm it is smooth.

I thought about sticky valves, but compression is 100 across the banks and vacuum test was solid with no flutter. I'm already a MMO believer.

[Tinker]

Originally Posted by FlatheadTed

Screwing them in shouldn't stop the motor as it feeds around the plate, I vote dirt in the idle jets or to small ,also look at the spray tubes ,check the winter and summer setting, Could be a hair line crack in the manifold ? Ted

I'll check this as well. thanks

[G.M.]

Originally Posted by Tinker

I'll give this a shot. thank you.



Geez I hope it's not guides. The engine is a older (4-5 yrs) rebuild with very little miles (500 miles).



It does buck in high gear at low speeds, really anytime its near a "lugging" condition (hills, etc). Also when starting out or whenever the motor drops down to a lower rpm (gear change). If the motor is running a decent rpm it is smooth.

I thought about sticky valves, but compression is 100 across the banks and vacuum test was solid with no flutter. I'm already a MMO believer.

You have the conditions I described. For $5.00 ty the MMO. G.M.

[Tinker]

Originally Posted by G.M.

You have the conditions I described. For $5.00 ty the MMO. G.M.

I've used it for yrs and have two bottles in the shop almost always. It gets a shot every once in a while and on Saturday I did drizzle some down the carb till it smoked out.

I'll try the procedure you mentioned when I get a chance.

I ordered a new intake gasket and I might just open it up if I can't get these other options to work.

[Tinker]

Well followup from this evenings tinkery.

Picked up another ih200 and installed it.

Warmed the truck up some then drizzled MMO for a bit, smoked out the garage (door was open). Good thing MMO smells good. Then let it sit a couple hours.

Fresh (non-oxygenated/ethfree) gas and MMO.

Took it out and drove it. After a bit it leveled out and the hesitation is almost gone. So GM I might owe you a hamburger and a coke! . Strange how the compression and vacuum tests did not pick it up?

Since I did both the condenser and MMO it could be either possibly. But I'm not going to change out that condenser to find out. Popping is gone.

I'll have to see how it runs tomorrow but I have hope now! Might have to finally get some decent mufflers on it.

I do still get a little surging at idle, like a luppy cam.