I have a 1950's H model and it is giving me fits. After cleaning out the carb, using the block heater, and charging the 6-volt battery I got it going so I can try to plow out driveway. After 15-20 minutes in which it has been running okay, it starts to stall like fuel starved. I choke it and that keeps it going but I hear this hissing. I then play this back and forth of choke and no choke and it runs bad. Very frustrating. My thought is as the head gets hot the gasket (head) is leaking air? or the carb to intake manifold is loose? Ideas? Also, I would like to convert to 12 Volt. Do I need to change out starter?
- Thread starter Adobejoe
- Start date
Janicholson
Well-known Member
The intake manifold is likely loose. A Hitachi 14231 for a mid 80s Nissan PU is perfect, and fits easily. On the diagram,
leave out the blue small wire from the starter to the ballast resistor. Jim
Wiring for alternator
leave out the blue small wire from the starter to the ballast resistor. Jim
Wiring for alternator
jimg.allentown
Well-known Member
Hissing noises indicate a vacuum leak. You should be able to pinpoint the leak by spraying some carb cleaner around suspected leaks. You can also listen through a piece of rubber hose used like a stethoscope.
Most likely places to leak are intake manifold gasket, carb gasket, crack in manifold, and any vacuum lines that may have come off. If there is a vacuum fitting on the carb, it may have had a cap on it that could have come off.
Head gaskets would not normally cause a hissing noise or vacuum leak.
Most likely places to leak are intake manifold gasket, carb gasket, crack in manifold, and any vacuum lines that may have come off. If there is a vacuum fitting on the carb, it may have had a cap on it that could have come off.
Head gaskets would not normally cause a hissing noise or vacuum leak.
I can try to tighten intake manifold, but I suspect the gasket, or a crack, as someone mentioned. I have another old IH I can pirate parts from so that might help. There are about 6-8 bolts on studs attaching the combined intake/exhaust manifold to the block. Another possible issue is stale gas...it has been sitting 6-10 months. These old tractors are great when they run, but can give one fits.
john *.?-!.* cub owner
Well-known Member
If you have the air cleaner pipe off, the hiss may be air passing the choke plate.
Andy Martin
Well-known Member
And no, the starter does not need to be changed. It will turn the right direction with positive or negative ground and I have run 6v starters for many years on 12v with no failures.
Steve@Advance
Well-known Member
I agree with Goose, what you are hearing is probably air sucking into the gas tank. Possibly the vent in the cap is blocked with ice if it was below freezing.
Or it could be a vacuum leak, but that should be constant, not happen after running 20 minutes.
As for the starter, most leave the 6v starter on. If you are careful not to crank on it too long, the starter windings will handle 12v just fine.
But... Some tractors handle the hard hitting 6v starter better than others. The problems can be broken drive gear, damaged flywheel gear, broken starter housings, etc., while others seem to have no problems at all. Depends on the design, how hard the engine starts, and how often it is started. Something that may lessen the damage is to use a low CCA battery.
Or it could be a vacuum leak, but that should be constant, not happen after running 20 minutes.
As for the starter, most leave the 6v starter on. If you are careful not to crank on it too long, the starter windings will handle 12v just fine.
But... Some tractors handle the hard hitting 6v starter better than others. The problems can be broken drive gear, damaged flywheel gear, broken starter housings, etc., while others seem to have no problems at all. Depends on the design, how hard the engine starts, and how often it is started. Something that may lessen the damage is to use a low CCA battery.
I find it hard to believe the fuel tank cap could be causing this noise, but I know there was a recall on the original fuel tank caps and I have a larger black cylindrical cap installed many years ago. I think when I close the choke to keep the engine running it is causing a huge suction or pressure change in the carb /manifold body and that becaseu this only happens after the engine has been running 15-20 minutes the hot metals have expanded and there is a hold in the manifold gasket. I will pull the manifolds tomorrow and inspect, likely replace manifold gasket and look for any hairline cracks. Also replace gasket between carb and manifold.
Fuel flow was bad so I drained tank and checked glass vial/valve. Found piece of cutter bee hives...they are pesky around here, that was reducing fuel flow. Cleaned and it started okay. I think the hiss sound now might of been airflow around chock plate. Tractor ran, although somewhat rough, a few pops and so forth. I cleaned points with some fine sandpaper and that helped. Wish I knew what the dwell setting should be so I can check points or gap. I think either the plugs and/or coil might just be worn out. Will think about 6-12 volt conversion. Basically replace generator with alternator. Thanks for inputs.
Similar threads
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.
Copyright © 1997-2024 Yesterday's Tractor Co.
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy