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Discussion Starter · #1 ·
Just came into possession of a running in decent shape push mower. I had to get into the carb some and clean it up but it runs for now. It needs some new belts ( looking for part #'s ) and need to know if the throttle on this mower is correct. Got the electric start working with a battery I had laying around in the garage but the bracket isn't factory. It winds over slow but with the throttle in the start position is takes a couple of times to get the old girl fired up. Pull start works great... Must keep the throttle all the way forward in the start position for some time ( 2 mins ) before I can let it back otherwise it dies. Here's my question... Is the throttle on this thing variable in speed meaning is it suppose to slowly wind down as the throttle position goes back towards the off position? Mine pretty much stays max throttle until it hits the stop position, so no slow idle and not sure if this is normal or not...
Here's some info on the unit..

Snapper 4 hp Hi Vac
Model 21401PS
Serial # 64244222

On the B&S engine
Model 110907
Type 3913-01
Code 86032404

I believe it's a 1986 model, 11 cubic in, Vertical, Pulsa-jet, electric start, gear drive, with alternator.

Can anyone confirm my info and shed some light on the situation...

Here's some pics...







Mike
 

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Model 21401PS
21 inch
4 HP
Series 01
PS Pull Start (I believe)
I can't confirm the year but I'll see if I can find a manual for it if you don't have one.
Nice mower, I do like the old Snappers. :2th:
 

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When you cleaned the carburetor did you replace the diaphragm with a new B&S 391681 diaphragm? If not, that is your problem. Make sure that the carburetor spring and cap are installed correctly. If either is missing, full fuel consumption will be higher than normal, or the diaphragm will tear. The B&S Part numbers are [FONT=&quot]690766 and 260455 for the spring and cap. The spring and cap are mounted on the carburetor side, NOT IN THE TANK!!! At this time it is also a good idea to clean the two fuel screens which protrude into the tank. These are kool-bore engines, and when properly set up they will always start on the first pull. The pulsa jet carburetor has an auto choke built into it which is controlled by the diaphragm. Always set the throttle lever to full when starting! Throttle response should be fast and accurate. Set the engine to run at 3400rpm governed speed and it will last forever and then some. It is a great mower, I have many with over 3000 lawns on them! I can usually get about 3 years out of them working commercially before I need to flatten the head and replace valves and valve guides!

Chris



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Discussion Starter · #5 ·
Thanks Guys, appreciate the help!
It definitely won't start on the first pull or the first crank of the starter. I'll try to round up the parts you mentioned and go through the carb.
Any chance anyone knows the part #'s for the belts?
 

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The belts are Snapper 7012354 and Snapper 7012508. The belts can be a pain in the you know what to change. It is easiest to change if you remove the two springs, one on the drive plate, and the other on the belt tensioner. Then remove the nut on the bottom of the drive plate, and work the V belt on. Then remove the two 1/2" nuts on the side of the transmission, and slide that mount off. That little 5 rib serpentine belt can take a while to get on if you know what I mean! Your mower does not look too worn, but you never know. It is a good time to check the two cast aluminum serpentine belts for wear. Over time those ribs will wear down and the drive wheels will not engage like they should. The Snapper pulleys are part 7024521 and 7019213. Last but not least, it would be a good idea to check the fluid level in the transmission. Open the plastic top cover, and look inside. Grease should come 3/4" of the way up the large drive gear. When you spin the wheels, the top gear should be covered in grease. The grease to use is "00" grease. It is about $20, and to my knowledge there is no suitable replacement! If you try to use motor oil or a medium grease, oil will either leak past the seals, or it will just cling to the sides of the case and the transmission will fail due to lack of lubrication. Once you service the mower, it will provide you with many years of trouble free use. However I must warn you, collecting vintage Snappers is contagious. Once you have one, you will only want more!

Chris
 

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Discussion Starter · #9 ·
The belts are Snapper 7012354 and Snapper 7012508. The belts can be a pain in the you know what to change. It is easiest to change if you remove the two springs, one on the drive plate, and the other on the belt tensioner. Then remove the nut on the bottom of the drive plate, and work the V belt on. Then remove the two 1/2" nuts on the side of the transmission, and slide that mount off. That little 5 rib serpentine belt can take a while to get on if you know what I mean! Your mower does not look too worn, but you never know. It is a good time to check the two cast aluminum serpentine belts for wear. Over time those ribs will wear down and the drive wheels will not engage like they should. The Snapper pulleys are part 7024521 and 7019213. Last but not least, it would be a good idea to check the fluid level in the transmission. Open the plastic top cover, and look inside. Grease should come 3/4" of the way up the large drive gear. When you spin the wheels, the top gear should be covered in grease. The grease to use is "00" grease. It is about $20, and to my knowledge there is no suitable replacement! If you try to use motor oil or a medium grease, oil will either leak past the seals, or it will just cling to the sides of the case and the transmission will fail due to lack of lubrication. Once you service the mower, it will provide you with many years of trouble free use. However I must warn you, collecting vintage Snappers is contagious. Once you have one, you will only want more!

Chris
Thanks again Chris....
I already have a collection of mowers but this is my first Snapper. I have 2 frankenmowers, 1 66 MF10 and 1 75 Bolens H14 to fulfill my mowing needs. One of the Fankenmowers is my go to machine and loaner. It's a Craftsman with a donor engine which has been working like a charm since I performed the transplant in 2004.
I checked the RPM today (2950 ) and adjusted the fuel screw. So, it starts better but how do increase the rpm? Governor link or spring position?
 

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You should always adjust the governed speed of the engine with the governor arm on the side of the engine! A small adjustment makes a big change in overall engine rpm, so loosen the locknut on the governor arm just enough that you can rotate the arm. Move the upper tip of the arm about 1/8" and lock the nut down. Check rpm with a handheld electric tachometer. If the engine starts screaming past 3600, shut it down and move the arm the other way! Once the full fuel setting is set to 3400-3450, lock the governor retention nut in place, mow the yard for a minute and then double check the governed rpm of the engine before putting the mower away. Idle rpm is about 800 from memory. If the engine does not idle well, there are three things you should check for, vacuum leaks around the intake crossover tube, the carburetors diaphragm itself, and a little less likely - the fuel tank flatness. B&S made a fix for warped fuel tanks which is a little roll pin which you center the carburetor and diaphragm onto the tank with. It simply positions the tank better so that when you tighten the 5 carburetor mounting screws in place, everything lines up like it was meant to. By the way, I always start my 21401P's with the throttle in the full fuel position, and bring it down to idle after it initially starts. If it is still taking a bunch of pulls to start, even after going through the carburetor, give the ignition a look through. Sand the magnets on the flywheel and gap the coil. I think the coil gap is 0.012"

Chris
 

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You should always adjust the governed speed of the engine with the governor arm on the side of the engine! A small adjustment makes a big change in overall engine rpm, so loosen the locknut on the governor arm just enough that you can rotate the arm. Move the upper tip of the arm about 1/8" and lock the nut down....
Sure about that Chris? I'm thinking that engine has an air vane governor on it with no adjustment. Which would mean the back tension spring on it has stretched a little and needs replaced or the linkage to it is bent some. By one of my books recommended idle was 1750-1800 to keep cooling and lubrication in the safe zone. :2cents:
 

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Sure about that Chris? I'm thinking that engine has an air vane governor on it with no adjustment. Which would mean the back tension spring on it has stretched a little and needs replaced or the linkage to it is bent some. By one of my books recommended idle was 1750-1800 to keep cooling and lubrication in the safe zone. :2cents:
Yeah, I was a little confused as well as I have a snapper with basically the same engine and I didn't recall seeing any kind of adjustable arm.
 

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5 of my 8 Snapper 21X01P's have Briggs engines, and all of them have mechanical governors! Its time that you guys open up your B&S repair manual and take a read through section 5!

I know mine have mechanical governors, since I have rebuilt all of the B&S engines on them, some even twice because they have so many hours on them. The oil slinger is part of the governor drive gear on these engines!

I have never seen a 21X01P with a 9000, 11000, or 14000 series Briggs with an air vane governor. If it does have one, you can only change governed speed by changing the governor spring tension by moving the spring to a different hole, or by replacing the spring with a stiffer one.

Mark, you are correct with the 1750 idle rpm. I choose to run mine slower, since I operate a business with them, and sometimes you really need the engine idling slow so that it cuts but will not throw rocks!

Chris
 

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...I have never seen a 21X01P with a 9000, 11000, or 14000 series Briggs with an air vane governor. If it does have one, you can only change governed speed by changing the governor spring tension by moving the spring to a different hole, or by replacing the spring with a stiffer one. ....
My old boss had a Snapper (no idea what the specific model of it was) about that same vintage I used to mow at work about 10 years ago for awhile. I did not recall it having the mechanical governor. I went to Briggs website and using the OP's numbers (110907 Type 3913-01 Code 86032404 ) pulled up the parts list for the 110900-110999 model series.

http://www.briggsandstratton.com/us/en/document/index?doc=MS8165_LO.pdf

Turns out that model series had both types. Looks like type codes below 3900 series were air vane and type 3900 and above were mechanical.
 
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