Jump to content

Unofficial Home of Old Simplicity & Allis-Chalmers Garden Tractors

Sign in to follow this  
Viva-la-B-110

B-110 choking down

Recommended Posts

Viva-la-B-110
I've got a '68 B-110 that I repowered with a 16 HP Briggs that was an exact match of the original engine, just more power. My only issue is that when I go out to mow (or mulch leaves as the case is right now), it will run perfectly for about 15 minutes and then starts to choke down. If I pull out the choke that will give a boost of a few seconds but it coughs and sputters and eventually dies. After letting it cool off I can repeat this process until I have mowed my yard (which is sizable) 15 minutes at a time. I've replaced the gas cap, checked the gas flow, put in a new spark plug, cleaned the air filter, and used card and choke cleaner (even though the carb is brand new out of the box). Any tips?

Share this post


Link to post
Share on other sites
RayS
make sure the screen in the tank doesn`t got stuff clogging it. Had your same issue or simular and that screen would pull crud around it and have me messing with choke and carb adjustments. Motor was brand new. I broke the screen off and haven`t had a issue since. Would run 20 minutes and start acting up.

Share this post


Link to post
Share on other sites
dentwizz
Check your fuel lines too. The 16 is probably a bit more draw so it would need a good fuel line run to keep the bowl full. It doesn't take much to restrict through a bend. Make sure it is automotive grade fuel line not hardware store and that it is not cracked or stiff.

Share this post


Link to post
Share on other sites
perry
try and clean and gap points. but i bet it is the coil. i have had a few engines do this. i put a external 12V coil on one engine and that fixed it . my Allis big ten with 16hp has been acting up all summer. wont run past half throttle when first started. then it clears up after 5min and runs fine. does it everytime i go to mow the grass. i am positive the coil is going out. i have done all other cleaning and adjustments .

Share this post


Link to post
Share on other sites
dentwizz
That would seem odd to me to be electrical if that goes away after 5 mins. Typically electrical issues get worse with increased temperature(that I have seen anyhow). Just a thought.

Share this post


Link to post
Share on other sites
perry
quote:
Originally posted by dentwizz
That would seem odd to me to be electrical if that goes away after 5 mins. Typically electrical issues get worse with increased temperature(that I have seen anyhow). Just a thought.
ya i know. that's why i have not pulled the engine to change the coil yet :D. but i have done everything else. i skipped a week mowing and it took about 10min to clear up last Saturday. wont go over half throttle until its ready . just trying to finish out the mowing season. want to put a 10hp back in it. sure don't need the 16 in a mowing tractor . weird is once it clears up it will run all day without a fuss. but my other 16hp acted the exact way, but once it would not go over half throttle it stayed like that untill i changed the coil.

Share this post


Link to post
Share on other sites
dentwizz
When my 23D did that(which it did for a while) it turned out to be insufficient float level in the carb and a minor kink in the line where it was being hit by the choke cable. The line they give from the hardware store was way too easy to pinch off compared to the SAE grade automotive stuff.

Share this post


Link to post
Share on other sites
Viva-la-B-110
Thanks for all the advice... It is a nearly new automotive grade fuel line. But it's possible that there may be some debris choking it off in the tank, considering that it is still the original tank and screen. On the issue of the coil though, I'm going to go ahead and admit my ignorance... I have no real clue what that is, where it's located, what it does, or how to replace it. I've been tinkering with this machine for some years and know quite a bit, but I always love learning new things.

Share this post


Link to post
Share on other sites
jbird243
When your engine shuts off after running 15 mins. Check for spark --- if you have spark with a hot engine the coil should be ok. Buy a spark tester for less than 10$ --- it helps to find problems. You have to pull the engine, the cooling shroud, and the flywheel to change the coil on briggs CI horizontal crank engines. --- big job.

Share this post


Link to post
Share on other sites
Viva-la-B-110
I ran it today until it died and checked the spark-- it had a small blue spark and I could feel the electrical charge(possible not too smart). Then I ran it again until it died to check the fuel flow, which was good. I'm running out of ideas here. Today it ran strong and smooth until it just died, no choking down-- just quit as if you'd shut off the key.

Share this post


Link to post
Share on other sites
HubbardRA
Check your valve clearances. As an engine heats up, the valve stems actually get longer, since metal expands when heated. With insufficient clearance in one of the valves, it can heat up till it quits sealing and the engine will start to run rough, then quit. When mine was like that sometimes it would just quit, sometimes it would run rough first. That was about 15 to 20 minutes of mowing on my tractor. When I put the right amount of clearance in the valves, it no longer shuts down after getting hot. Most people think that the valve clearance will get larger with engine age because of wear. With these older engines it is just the opposite. Over years of operation the valve constantly beats against the seat in the cast iron block. This causes the seat to wear deeper into the casting. These engines do not have hardened inserts, just a seat machined into the casting. As the seat wears deeper, the valve clearance goes away. If the valve clearance is never checked and corrected, it will eventually go to 0 with usage. So far I have fixed this problem on three different engines. When nothing else is left, then check the valves. You can get to them by removing the crankcase vent mechanism which sits behind the carb on a B/S engine. To add clearance just insert a file between the valve stem and the lifter and file off a little metal. Be sure to do this slowly and check with a feeler gauge. You can't put the metal back if you take off too much.

Share this post


Link to post
Share on other sites
robob
If it stalls as if you turned the key off i don't think it's fuel related ck to be sure the wiring harness isn't trapped after the engine swap especially the shut off GRN wire to the key switch.

Share this post


Link to post
Share on other sites
joelk
I had the exact same problem on my 12HP 3112. It would run fine for 15 minutes and then start coughing etc. As Ray stated, I took the screen out of the tank completely and it has run perfectly since (1 snow and one cutting season).

Share this post


Link to post
Share on other sites
JimDk
Rod, That is a great post on valve clearance. It is often overlooked when our old engines don't run well. To add a little info, I set my valves close to .009 for the intake, and .018 for the exhaust. That seems to work ok and is the clearance called for in the specs.

Share this post


Link to post
Share on other sites
Willy
How's the vent in your gas cap?? My B-12 dose the same thing I put an external coil on it now it works fine' When it stalls try taking the fuel line loose to check your fuel flow,if it's restricted take an air hose and give it a shot back through, if the tank screen is plugged you will either clear the screen or blow it loose either way you get fuel. Good Luck

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this  

×