Carrier engine problem

[Jim Burrill]

Guys, I have been having a problem with Barry Detweiler's carrier for several weeks now. I posted to the MV list and followed several suggestions but still have the problem.

Indication: Starts and idles fine. Put your foot into the accelorator and it bogs down... about 80% of the time.

So far: Used a pony bottle with clean gas/ drained tank, cleaned filters and used fresh gas/changed fuel filters/replaced fuel pump/measuered the length for the pump rod (it was exactly the same as a new replacement I had ordered)/replaced the coil/replaced the plugs/
and today, I just rebuilt the Zenith 28 carb with a carb kit from Treadwell Carbs (fine people!)

Haven't changed the rotor cap, conensor or otherwise messed with the distributor.

It's liek it will sit and idle sweet all day long.... just totally bog down if you are pressing hard on the accelerator. I can rev the engine fine if I move the control gently.

ANy ideas?

[Alex Blair (RIP)]

Sounds like it is not advancing..like the centrifugal weights are seized in the dist..or the in and out valve is stuck..
I don't know what dist you have but I would go for the advance mechinism..
Or the giggiling pin...

[chris vickery]

JIm, Your problem sounds to me very much like the distributor. I have messed around with flathead distributors quite a bit and the one thing I can tell you is that they are generally a pain in the a**. The worst style is the earliest being the diver's helmet used from 1937 to 41. Of course, this is the style utilized on the UC. The main problem I have encountered is usually the coil mounted on top tends to overheat and breakdown dropping the output voltage to less than ideal. To give you an idea, early coils were lucky to put out much more than I'd say 15,000 volts. Upon thermal breakdown you lose adequate voltage failing to ensure proper firing. Another possibility is that the centrifugal advance weights are stuck, lose or old, the timing cycle bad etc. By the way, any books that suggest a method of setting the timing eg. a carrier manual, by hand are garbage. The only answer is to find someone with the proper fixture for setting flathead distributors.
Trust me, I've seen this so many times it's not funny, but everyone has an opinion as to the miracle cure, NO it couldn't possibly be the dist. or something like that. Good Luck!

[Bob Moseley (RIP)]

Hi Jim

Although our flatheads utilise different carbys and the fact that you have rebuilt yours, it still sounds like fuel starvation. A common problem we encounter is a worn out power valve. Another interesting and frustrating problem was overcome when we discovered that the small ball located under the accelerating pump was missing.

Bob

[Jim Burrill]

Chris and Blair, thanks for your suggestions.

While we were working on the carrier, I had noticed a second problem with the lights and gauges. We dropped the instrument cluster down to replace a blown fuse. With that replaced the gauges came on line and front headlights work.

Then I noticed that the headlamp was very dim after a few minutes (this with the motor running). Thought that was odd, but I had more pressing issues with the Carb.

After a phone call to Barry Churcher *thanks Barry!* I decided to go back and look into the voltage situation.

The carrier currently has a tractor 8V battery in the normal spot. A second battery is mounted in the wireless battery area. It is a 12v battery connected directly to the starter and activated with a 6v solenoid connected to the starter button in the instrument cluster.
BTW, I copied this set up (except with a stock 6v battery vice 8V) in my Mk1.

Ok, I measured the voltage with the engine running and I only have 3.7 VDC. Today I am going to adjust the 3rd brush on the generator and see what happens. I am not sure if that will up the actual voltage or simply encrease the current flow for the charge rate. The manual simply says it increases the rate of charge. My 'tron theory is a bit rusty and I am not sure how the 3rd brush is providing juice. (Hmmmmm..... is 7.4VDC the typical generator output when running? I have half that...Could have lost a brush?)

The generator lamp had been burned out and we replaced it when we had the instrument cluster apart. It stays on all the time now, dimly. Last night before we called it quits, it was running much brighter.

I know - the lamp indicates current flow back to the battery, so any light means the battery is drawing current to recharge. With an 8v tractor batttery, would it ever go out?

The ammeter is suspect anyway. Tapping the glass changes the display everytime.

The voltage cutout is original. The distributor was updated to be the crab style.

I plan to send off for a new cutout, dash resister, dist cover and whatever else I can get short of pulling the distributor out.

Wish me luck.....

Cheers,
Jim

[chris vickery]

Jim, a generator operating at proper voltage should be charging at a rate of approx 7.4vdc. Resisted voltage to the dist. should be about half that.

[greg anderson (RIP)]

1.Look down carb barrel with carb bowl full and engine off-when you open throttle you should see power jet discharging gas--2.Plugs will spark at idle but when throttle opens compression rises and plugs do not get sufficient voltage to spark--check to see that voltage at coil primary is O.K.--also check your coil noting you are using a later dist. hopefully with a better coil--greg

[cletrac (RIP)]

With a point distributer system a bad condensor will usually act like a fuel problem. A new condensor might solve the problem. It sounds like spark to me.

[Alex Blair (RIP)]

Jim
We were though the identical problem with Stu's carrier a while ago..
Change that dist..
Those old crab style distributers were called that because they were crabby..acting and to work on..
Go to a new crab type here or an up dated one can be changed over..Available at the Flat head sped shop..
http://www.flatattackracing.com/

[Jim Burrill]

The Battery!!!

With the carrier consistantly running at idle but dieing as you try to step on the gas, I called the mechanic who got my carrier running. He was gracious enough to do some head scratchin' with me over the phone at no charge.

He explained that the old flathead cutout on the generator puts the battery into play as part of the voltage stabilizer circuit in a modern car.

He said that if the battery had a bad cell, and was putting out low voltage and not charging properly, it would draw current from the ignition path.

Although I had just recharged the year old battery again to where the green "full charge" light was on at the charger, the lights dimmed quickly and the vehicle ran as I described.

So, we went out and got a new 6VDC battery, installed it, and it runs! Runs without any of the previous problems.

We shut it down for the night and tried again today and it started fine. Then went out and tore up my side yard driving the carrier. After 30 min of runtime, we could not duplicate the problem.

Keep in mind, the laast time I had shut the carrier off was with it consistantly running badly, the only thing done different was to replace the battery.

I still have the rotor cap, and points in the mail. I will keep them as spares and will take them with us to the field tactical. If the carrier acts up again, I will replace those.

Ok, this is going to be a "one for the books" war story whenever engine probles arise on a carrier.

Thanks to everyone who took the time to respond with great suggestions!

Cheers
Jim

[Bob Moseley (RIP)]

Jim

This has been an excellent posting with so many tips. I'm printing this one off to put into my Tips Book.

And isn't it always the case, a frustrating problem with eventually a simple solution.

Bob