Running rough...need your help

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Model T Ford Forum: Forum 2015: Running rough...need your help
Top of pagePrevious messageNext messageBottom of page Link to this message  By dan kuffel on Wednesday, October 28, 2015 - 11:09 am:

Hi Everyone, I need your help again. My 21 project is looking great with a new open express body on it. But I am having trouble getting it to run smooth again. When I first put it all back together it ran like a dream. Smooth as could be. Then one day I had planned to take a cruise and when I fired it up it would barely run. Seemed like it was starving for gas or something. So this is what I have done so far...8 gallons of fresh gas, installed a new fuel pump at the suggestion of another T owner, checked the plugs and re-gapped 2, cleaned out the carb best I could, polished the points. I cant figure out why one day it ran so well and the next time it would barely run. I dont have another carb to try but maybe I need to find one. Any tips or suggestions from you pros would be greatly appreciated.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Wednesday, October 28, 2015 - 11:14 am:

Do you have std coils and timer?
If so, take off the timer and clean/check it. If it's a timer that's supposed to be oiled, then oil it. Often.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Henry Petrino in Modesto, CA on Wednesday, October 28, 2015 - 11:24 am:

Check to be sure the gas tank cap vent hole is clear.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Thomas Mullin on Wednesday, October 28, 2015 - 11:31 am:

Dan,Are you running a distributer and a fuel pump?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Wednesday, October 28, 2015 - 12:22 pm:

My question(s) are why are you running a fuel pump, what carb and as Roger asked, are you using coils and have they been checked?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Wednesday, October 28, 2015 - 12:38 pm:

Do you have a clean fuel line and sediment bulb? A fuel pump won't help if the fuel line is clogged. Unless you have a downdraft carburetor, a fuel pump is not necessary at all.

since it ran fine and then when you started it up suddenly it ran rough, I would think it would be possibly a fuel clog or maybe an ignition problem. However, have you checked the compression? Sometimes if an engine has been parked for a while, a valve will stick in the open position and that cylinder won't work. If you have zero or very low compression in one cylinder, it could be a stuck or badly burnt valve. However I think a burnt valve problem would come on gradually, but a stuck valve might appear suddenly.

Another possibility would be a faulty ignition switch or a problem with the magneto. Anyway, please give us some more information as to which after market or non-stock parts you have in the fuel and ignition system so that we will be better able to diagnose your problem.
Norm

A sudden


Top of pagePrevious messageNext messageBottom of page Link to this message  By R. S. Cruickshank on Wednesday, October 28, 2015 - 01:29 pm:

Before I did any extensive "take apart work" I would check for a vacuum leak. Because you have apparently just put this together, the manifold may have gotten loose and letting air past the gaskets. It is an easy thing to check before any major work is done. Just my .02. Dick C.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Menzies on Wednesday, October 28, 2015 - 02:19 pm:

Because the spark plugs are pipe threads they are prone to leaking. When it is running spray a little water in the spark plug depressions and check for leaks. Most leak a little but excessive can cause some erratic behavior. This is a quick and simple diagnostic test.


Top of pagePrevious messageNext messageBottom of page Link to this message  By dan kuffel on Wednesday, October 28, 2015 - 02:47 pm:

thank you all for the quick responses.
I have a distributor on this T. It is an Algonquin Electric.
There is great deal of compression but I havent put anything on to measure it.
Fuel tank, sediment bulb and fuel lines are all brand new. I will check the vent on the cap. When I remove the fuel line from carb I seem to get adequate fuel coming thru. Looks unblocked to me. Cant say what happens inside the carb. Are there any parts of the carb that need routine maintenance?
I put the fuel pump on based on the recommendation of a T guy that has been doing this stuff for 60 years. He said his sons car did the same thing and a fuel pump took care of the problem. It is a Model NH Carb.
Also it doesnt sound at all like only missing on a single cylinder.
Anyway thanks again for all the replies.


Top of pagePrevious messageNext messageBottom of page Link to this message  By R. S. Cruickshank on Wednesday, October 28, 2015 - 09:12 pm:

Hey Dan!!! What about the vacuum leak potential?? The reason I suggest this is experience with some of my Ts considering that you changed the carb and may have loosened the manifold. The carb has a gasket and the manifold has six. Two are directly related to the input (intake vacuum).


Top of pagePrevious messageNext messageBottom of page Link to this message  By dan kuffel on Wednesday, October 28, 2015 - 09:15 pm:

I checked all the manifold bolts and I cant turn any. They all seem as tight as can be. Shoudl I remove the manifold and inspect the gaskets?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Dufault on Wednesday, October 28, 2015 - 09:58 pm:

Not yet...

Bolts could be tight, but there still could be a leak...read this:

http://www.mtfca.com/discus/messages/411944/460433.html?1405129225

Also to consider - did you use any type of paste or teflon tape when you assembled the gas line to the carb? Is there a possibility that some debris is plugging the carb gas inlet?


Top of pagePrevious messageNext messageBottom of page Link to this message  By dan kuffel on Wednesday, October 28, 2015 - 10:18 pm:

I will give that a try. I did use some teflon tape but removed it when I put it all back together after disambling and cleaning the carb parts. I dont think that is the problem. If the carburator float valve and seat set is not functioning properly would it be able to cause this type of problem?


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dewey, N. California on Thursday, October 29, 2015 - 01:15 am:

One has to be very careful with teflon tape and carburetors--the tape tends to come apart where it's not trapped by the threaded fittings and plugs up jets or passages.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Schedler, Sacramento on Thursday, October 29, 2015 - 01:55 am:

I didn't read this entire thread so this may be redundant.

At idle or slightly above, spray WD 40 where the intake manifold meets the engine. If you get an increase in RPM or a change in the sound of the engine in any way, you have a leak.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Stroud on Thursday, October 29, 2015 - 02:43 am:

A bad condenser can drive you nuts! Don't rule that out.(I assume the dizzy has one?) Even a new one can be bad, especially these days(Read non USA manufacture). I've had a few that were bad over the years, not one acted the same way. Just a thought. Dave


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Thursday, October 29, 2015 - 09:11 am:

With a distributor, be sure to check the points and the shaft. The points should not be burnt and pitted, and the gap should be around .018. The shaft bushings should be tight enough that the shaft does not move sideways which will change the point gap. A good condenser is also necessary as noted above. The rotor and cap should not be burnt and the rotor should point to the contact which connects to spark plug #1 when piston #1 is just past top dead center. With the spark retarded the spark should come just after the piston passes top dead center. And you should have a strong spark.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By dan kuffel on Saturday, October 31, 2015 - 06:40 pm:

so no leak found with the test of the intake manifold.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Derocher on Saturday, October 31, 2015 - 09:14 pm:

I would go with David and Norm, - points, wires grounding out, condenser, look over all the wires to and from the dizzy, something changed...JD


Top of pagePrevious messageNext messageBottom of page Link to this message  By dan kuffel on Saturday, October 31, 2015 - 10:13 pm:

the distributor is an Algonquin Electric. Can you tell me if the poiints and condenser are available at oreileys or Autozone or just thru the antique auto places?


Top of pagePrevious messageNext messageBottom of page Link to this message  By dan kuffel on Saturday, October 31, 2015 - 10:16 pm:

and if it makes any difference I might add that this car sat untouched for several years before I bought it and finished it and ran it for the first time. It started right up and ran extremely well for a couple short, maybe 15 minute cruises right after. then sat only a couple weeks until I tried to go again and it was bad. thanks.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Sunday, November 01, 2015 - 01:00 am:

Dan:

If the dizzy had a new condenser installed by you then it might have been the wrong type. While the correct value of capacitor and working voltage is easy to find, the correct type of capacitor is often chosen and they will actually work - for a short time. If the condenser you have was fairly new then tell me more about it. If it is known good unit designed for Distributor then it probably is not the issue.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Sunday, November 01, 2015 - 06:08 am:

I think all 1920's T carbs has a drain petcock under the float bowl. Did you check the flow from there? Should be a good flow that lasts - check for a minute with a bucket under. If it seems ok, but still doesn't run right, then you may have to take the carb apart and clean it. But first.. Maybe you just have some crap in the main jet? With some luck that might disappear if you turn the adjuster screw out while revving the engine - then turn it back in :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Kossor - Kenilworth, NJ on Sunday, November 01, 2015 - 08:51 am:

John wrote: "the correct type of capacitor is often chosen and they will actually work - for a short time"

I believe John meant "the incorrect type of capacitor is often chosen and they will actually work - for a short time"

I know you have installed a new sediment bowl (hopefully with new sediment screen) but I would not rule that out for good. I experienced several instances of fuel starvation on my 1927 Touring after putting it back on the road after sitting for an unknown period of time. The engine would start running poorly and continue to degrade until it would stall and not start again until it sat for a few minutes; then would start right up and run for a few minutes before the cycle repeated. The sediment screen was filled with what looked like small paint chips (fuel tank coating peeling off?) This happened about 3 time but I learned the symptoms and removing the sediment bowl screen was the first thing I checked when that happened. Check the sediment screen to make sure debris did not accumulate just to rule that out.


Top of pagePrevious messageNext messageBottom of page Link to this message  By dan kuffel on Sunday, November 01, 2015 - 09:34 am:

I will check the screen, thanks. and it has the same points and condenser that were in it when I got it. I havent changed anything on that end yet. I have had the carb apart and cleaned the parts so to speak. I did what I would for a mower or snowblower or any small engine type carb. does this require any "specialized" attention? I will check the spark again too. once again I appreciate all your help!


Top of pagePrevious messageNext messageBottom of page Link to this message  By John C Codman on Sunday, November 01, 2015 - 10:37 am:

Mike, I had the same symptoms with my T. The eventual cure was to pull the tank (ugh!) and replace it with my spare that I had cleaned and coated. It purrs now.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Sunday, November 01, 2015 - 11:00 am:

Cleaning it once may not be enough if new crap comes from a tank full of it..
There are a few tricks with a NH carb, you may have to drill out three brass plugs to clean all the passages - but that's not needed for every cleaning. After cleaning you can thread the holes and put allen head set screws as plugs.

See this thread: https://www.google.se/url?sa=i&source=images&cd=&cad=rja&uact=8&ved=0CAUQjB1qFQo TCJWAkvDL78gCFaKNcgodAKMGXw&url=http%3A%2F%2Fwww.mtfca.com%2Fdiscus%2Fmessages%2 F179374%2F254361.html%3F1324502921&psig=AFQjCNFWdY26-Pjkf88a9CY-DVZoWHNgWA&ust=1 446479913742527&rct=j


Top of pagePrevious messageNext messageBottom of page Link to this message  By dan kuffel on Sunday, November 01, 2015 - 12:28 pm:

screen was clean. tank and bulb are new so shouldnt be any junk. i took fuel filter and pump out and ran the line direct from bulb to carb. greast flow, still running rough. i will check the spark again next. and then maybe the carb holes.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ross Harris on Sunday, November 01, 2015 - 06:29 pm:

not to hijack this post but I'm having the same problem, what should compression be all mine are 55 to 60 psi


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Sunday, November 01, 2015 - 07:17 pm:

Ross, that's very good compression - for a std head T, that is.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Todd, ............Red Deer, Alberta on Monday, November 02, 2015 - 11:18 am:

Maybe sticking valve(s). Try some top lube in the fuel.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Monday, November 02, 2015 - 01:29 pm:

Do a compression test.


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