M135 Engine Power Issue

[DJTaylor62]

I have a 1952 M135, while coming home from a event, we were on the highway an traveling about 45 MPH. All of a sudden it was like we lost power and could bearly get 30MPH. We got it home and figures we had a clogged fuel filter. We have 2 fuel filters on it one is an inline clear type with paper filter in it and after that we have another micro filter in it. Both filter were changed, no change in the power loss. Then we thought maybe the fuel pump was going bad and we had an extra so we changed that, no change in power loss. Truck idles smooth and starts right up. Anybody got any ideas what it could be?

 

[m1010plowboy]

Welcome aboard the crazy train. An Early Deuce can drive a guy nuts. Congrats on getting her home from a show.

There is "typically" a small screen filter in the carb inlet. That screen can get plugged up. Do you have one?

Do you have an internal fuel pump? If you do and you had a spare ......you must be lucky, rich or a brilliant hoarder. If it's an add on external pump let's start talking about how many GPM it's delivering and if it's in that 2-5 PSI range.

Possibly..... Reduced power can actually be a 'drag' on the drive-train. Any hot or warm hubs?
Are the brakes releasing?

When the air-pak begins to go south....or air sneaks in through the MC as a result of low brake fluid, odd 'friction' events can begin.

6 wheels in the air and starting the trouble shooting from the ground up may find troubles beyond the symptoms.

I've had points split at the hold down mount and give reduced power, air paks not releasing brakes, sticking emergency brake release and a loose plug wire all give a symptom of reduced power so let's start at the bottom.

Fuel has been a problem north of the 49th and I just dumped 15 gallons of contaminated juice out of my M135 yeasterday. Make sure it's not a fuel symptom or the famous $10,000.00 leaf floating around inside your fuel tank.

 

[NDT]

Mine did that once, it was the condenser.

 

[DUUANE]

X2 on the hoarding..i would check points for gap, buning and oxidation. New condenser. Then go at the harder stuff. While youre at it with the ignition, clean and grease your engine to chassis grounds. Its good PM.

Good luck..let us know what you find.

 

[DJTaylor62]

Will Check the for the screen at the carb, I am assuming it is where the fuel line comes in.

Yes we have an internal fuel pump and we got a bunch of parts with the duece when we bought it and there was a brand new one in the bunch.

No warm hubs and all brakes seem to be releasing, we just rebuilt the air pack as it was leaking fluid.

We pulled the distributor apart the other day points did not look bad, neither did cap or rotor but we are going to replace them just need to order another set. Any suggestion who who to order from?

Fuel tank is clean and we cleaned it out when we put the new fuel pump in.

 

[1944mb]

Mine had something wrong with the Huey Duey, you know part # AM in the figure. Also ended up replacing RR. The resistor ohm-ed out exactly the same as the old one. The truck would start but step on the gas and it would die like a fuel issue. Was maddening. This distributor has more crap, I mean parts in it then any ignition system I've messed with. I got these ignition parts from Memphis equip but I've heard tom wolmbolt has a bunch too. Not sure who else but many distributor have stuff if you ask them. They don't always list it on the sites

 

[CMPPhil]

Hi

If you pull the distributor for any reason don't forget to check that the gear on the shaft is tight to the shaft. I've had gears on 40s vintage Chevy trucks (Canadian Military Pattern) work loose and then break the pin. Latest similar lose of power and hard starting on any of my CMPs was corrosion on the points.

Keep us posted on what you find, love a good detective mystery.

Cheers Phil

 

[DJTaylor62]

ok here is the lastest. We have replaced a fuel line from the fuel filter to the carb, replace the plugs, points, condensor, Dist Cap and Rotor. At this point no change, still no power. We are thinking that the carb has a bad accelorator pump. And are going to rebuild the card. Anyone else have any other ideas?

 

[nattieleather]

Check your valves and your timing make sure something hasn't gone out of whack. Also with the 302 check to see if you have a exhaust manifold leak. On the 302 it's not a matter of if you will have one but when.

 

[m1010plowboy]

Walk us through the symptoms in more detail.

You say it starts up and idles. Can you get a full range of RPM when it's sitting there?

Does the motor sound strong through all ranges of RPM when the truck is parked?

An engine that isn't producing power while under load but runs fine just sounds tired. If it's not "drive train" related then it's time to pull 6 plugs and check compression. Checking compression before and after you set the valves is a groovy experiment.

Our latest M135 Gander, had 2 plug wires backwards with similar symptoms so sometimes the fix is simple and sometimes it's a journey. Keep jabbing that dog like you're doing, we'll get it.

 

[DUUANE]

These 302's are governed are they not? Could there be an issue there? Im not too familliar with them other than they are vaccuum operated/related..torn diaphram or broken spring allowing it to close early? I usually disconnect them or remove all together as i can drive and watch a tach at the same time.
Whats the big book of do's and dont's say Ploughboy?

 

[rustystud]

These 302's are governed are they not? Could there be an issue there? Im not too familliar with them other than they are vaccuum operated/related..torn diaphram or broken spring allowing it to close early? I usually disconnect them or remove all together as i can drive and watch a tach at the same time.
Whats the big book of do's and dont's say Ploughboy?

The governor can cause poor engine performance if it is malfunctioning. Usually it will not go much above idle though.

 

[DJTaylor62]

Yes truck idles fine and starts right up. Yes can get a full RPM range when sitting still and truck is parked. Motor sounds strong but stumbles like accelerator pump in carb is sticking. We are choosing to rebuild the carb at this point. Will report back when we get that done. Ordering carb kit today. And yes checking the compression is on our list also . Th.nks for the suggestions and help/

 

[1944mb]

You could run your choke out a little when accelerating engine in park and it should rev up. You could at least do that and see if there is a change. Also the accelerator pump wouldn't cause you to not get above 30mph over a long stretch in the interstate I wouldn't think. That's my two cents. Could be wrong.

Im with plowboy, a compressor test would be great to see what your valvetrain is doing. If that checks out you can also do a cylinder leak down test to see the condition of your engine. I realize the average guy doesn't have a cylinder leakage tester but they are invaluable for troubleshooting. In the end a carb rebuild is never a bad idea.

 

[CMPPhil]

Hi

Can you refresh my memory does this engine have manual or self adjusting valves? Reason I ask is that one of straight six engines in my CMPs went from full power to no power in 30 miles when one of the exhaust valves went to zero clearance. Engine running at full power cut away third of the value head.

The compression test as suggested should rule out or ID the problem.

Keep us posted on what you find.

Cheers Phil

 

[snowtrac nome]

don't rule out a worn cam bumper on the points. the wrong point gap will change timing and improper coil saturation will equate to a loss of power. also a bad condenser can cause the points to arc.

 

[DJTaylor62]

Well guys here's what we found out. Got a carb kit pull the carb apart. Found several things wrong with the carb, least of which was the governor was stuck open. One of the screws on a governor had fallen out and wedged it open. Rebuilt the carb put it back on adjusted it and the truck runs very well. To all those that put in a few cents thank you very much!

 

[CMPPhil]

Hi

Thanks for letting us know the end of the story. I hate when you read all the way through a mystery only to find that the last page with the big reveal is missing.

Cheers Phil