new member - simplicity 728 clutch & gear issues

[MinionKing]

Good evening all and thankyou for having me, ive trawled through the site as far as i could as a guest and so decided to sign up and hopefully get to chatting.

I recently bought a (i believe) 1969 simplicity 728 as a non running, mess of a project.

In the past 2 weeks I have completely stripped and rebuilt 90% of this tractor and I have to say Im in love with it. Engine has been fully rebuilt with new gaskets and seals, carb clean, new air filter, in line fuel filter added, new exhaust fitted, chassis welded, tyres replaced, all wiring replaced, all sanded back and resprayed back to (as close as i could get) the original colour. it now runs beautifully... thats where the good part ends  

I was so excited to drive this only to find the gear box and clutch seem to be the next issue.

so lets start with the clutch, very little movement despite being stripped, cleaned and greased. The tension pulley drops by maybe an inch to an inch a half but drive belt is still far to tight to stop the flywheel spinning. belts replaced, no difference. flywheel scrubbed with a wire brush, no difference. clutch & brake connecting bars adjusted, no difference. so with the tractor running i cannot get into gear without grinding the life out of it. 

Second issue, which may or may not be related. with the tractor off I can only move the selector into 1st or reverse, and finally the third issue (which again may or may not be related) is that the gears do not seem to be in the correct order, assuming the labels on the chassis are correct, 1st and reverse seem to be reversed. ( I was able to slip into gear and was shocked to find the tractor lurching forwards when I selected reverse lol. ) 

Last but not least, the tractor does not shut off at the Key. Starts no problem but wont shut off, Im assuming here that ive probably put a wire back in the wrong place for the kill switch.

Anyway thankyou for your time reading and thankyou in advance for any advice you feel like sharing  

Edited July 2, 2024 by MinionKing
missed some information out

[Chris727]

Welcome to SimpleTractors! These older Broadmoor series can be very touchy on the clutch adjustment. Many of these tractors have had the engines replaced at some point. Sometimes the original pulleys on the crankshaft get replaced with different ones. Sometimes they are not the correct size. If you don't have the correct pulley it requires adjusting beyond the specifications in the manual until you get it so it feels right. Do you have the manuals for this tractor and did you use belts to match the OEM specification? 

[Tarheel]

 Hello and welcome.

 The issue of the tractor not shutting off with the key. The engine makes it's own spark. This means that it will run without any wires connected. But to shut off the ignition, It must be grounded . You should find one wire from the key switch to the engine and this wire should be grounded when the key is off.

 I'll leave the trans-axle and clutch to those with much more recent hands on for this machine. Far to many year for me to try and guess.

[MinionKing]

13 hours ago, Chris727 said:

Welcome to SimpleTractors! These older Broadmoor series can be very touchy on the clutch adjustment. Many of these tractors have had the engines replaced at some point. Sometimes the original pulleys on the crankshaft get replaced with different ones. Sometimes they are not the correct size. If you don't have the correct pulley it requires adjusting beyond the specifications in the manual until you get it so it feels right. Do you have the manuals for this tractor and did you use belts to match the OEM specification? 

hi Chris, thankyou for your comment. so with the belt i took the original with me and matched one up for the size, as for the pulley the thought did cross my mind and wondered if it was the wrong pulley as it does seem fairly large. when the clutch is depressed as far as it will go, the pulley seems very close to the main flywheel which, if anything seems to put more strain on the belt. I'm not with the tractor right now but i believe the pulley is approx 3 inches across.

ive tried looking for manuals but unfortunately i cant find a serial number on the tractor to get the correct ones, i did find a link on here to a site with all the manuals but its asking for a S/N. 

 

[MinionKing]

10 hours ago, Tarheel said:

 Hello and welcome.

 The issue of the tractor not shutting off with the key. The engine makes it's own spark. This means that it will run without any wires connected. But to shut off the ignition, It must be grounded . You should find one wire from the key switch to the engine and this wire should be grounded when the key is off.

 I'll leave the trans-axle and clutch to those with much more recent hands on for this machine. Far to many year for me to try and guess.

thankyou for your response tarheel, i had suspected an issue with the ground wire, at the moment the only one i can see that seems to be the kill wire is one running from the ignition switch straight to a bolt on the side of the engine block attached to the choke wire mounting plate.

[simplewrench]

The wire from the ignition switch should go to the coil to kill the spark. 

[Tarheel]

1 hour ago, MinionKing said:

thankyou for your response tarheel, i had suspected an issue with the ground wire, at the moment the only one i can see that seems to be the kill wire is one running from the ignition switch straight to a bolt on the side of the engine block attached to the choke wire mounting plate.

 That should be the right one. Now, I can't recall how that switch was wired but it needs a ground. Most machines get ground through the wiring. A lead off the switch will go to chassis ground or to the battery - terminal. As old as that unit is, I guess it could be that the switch is grounded through the body. If that is the case then removing the switch and cleaning the inside before replacing it should fix your problem.

Good luck

[ShaunE]

21 hours ago, MinionKing said:

Second issue, which may or may not be related. with the tractor off I can only move the selector into 1st or reverse, and finally the third issue (which again may or may not be related) is that the gears do not seem to be in the correct order, assuming the labels on the chassis are correct, 1st and reverse seem to be reversed. ( I was able to slip into gear and was shocked to find the tractor lurching forwards when I selected reverse lol. ) 

This makes me think you have it twisted & routed incorrectly which would explain the tension being too tight & spinning the transmission in the wrong direction. Key would be if 2nd & 3rd also made it run backwards. 

[PhanDad]

32 minutes ago, Tarheel said:

at the moment the only one i can see that seems to be the kill wire is one running from the ignition switch straight to a bolt on the side of the engine block attached to the choke wire mounting plate

I don't think that wire is the "kill" wire.  Usually the "kill" wire runs from the ignition switch to an insulator tab.  The insulator tab is bolted to the block or on the older Briggs single cylinder engines the tab is bolted to the points cover.  The other end of the tab is a connection point where the "kill" wire from the ignition switch connects to the "kill" wire from the magneto (this wire runs until the blower housing tin).  Here's a poor pic of the insulator tab:

 

(The red wire is a replacement wire I ran from the ignition switch.)

I think your wire is a ground wire to the ignition switch.  As @Tarheel stated, many of the old tractors relied on frame ground for the ignition switch and sometimes a PO would run a separate wire for a good ground.  Or it is the ignition switch "kill" wire connected incorrectly.  

With a multi-meter you can test the ignition switch.  The "kill" wire is usually connected to the "M" tab.  The "M" tab is grounded when the ignition switch is "off" and in other positions, it isn't.  

 

[MinionKing]

1 hour ago, ShaunE said:

This makes me think you have it twisted & routed incorrectly which would explain the tension being too tight & spinning the transmission in the wrong direction. Key would be if 2nd & 3rd also made it run backwards. 

that would actually make sense Shaun, ill have to look into that one and make sure its routed correctly, thankyou

[MinionKing]

1 hour ago, PhanDad said:

I don't think that wire is the "kill" wire.  Usually the "kill" wire runs from the ignition switch to an insulator tab.  The insulator tab is bolted to the block or on the older Briggs single cylinder engines the tab is bolted to the points cover.  The other end of the tab is a connection point where the "kill" wire from the ignition switch connects to the "kill" wire from the magneto (this wire runs until the blower housing tin).  Here's a poor pic of the insulator tab:

 

(The red wire is a replacement wire I ran from the ignition switch.)

I think your wire is a ground wire to the ignition switch.  As @Tarheel stated, many of the old tractors relied on frame ground for the ignition switch and sometimes a PO would run a separate wire for a good ground.  Or it is the ignition switch "kill" wire connected incorrectly.  

With a multi-meter you can test the ignition switch.  The "kill" wire is usually connected to the "M" tab.  The "M" tab is grounded when the ignition switch is "off" and in other positions, it isn't.  

 

thanks for your input phandad, ill get the multi-meter out tomorrow and have a look at that. ill have to take some pictures of the wiring and hopefully someone can point me in the right direction as ive been having to follow what little information ive found online and since ive got no S/N for the tractor ive been struggling to the pinpoint the exact model.

[MinionKing]

1 hour ago, ShaunE said:

This makes me think you have it twisted & routed incorrectly which would explain the tension being too tight & spinning the transmission in the wrong direction. Key would be if 2nd & 3rd also made it run backwards. 

curiosity got the better of me here so had to pop down the workshop. 100% correct, belt was twisted and spinning the flywheel the wrong way. pretty obvious bloody mistake now i think about it 🤣 thankyou kindly for pointing that one out although im sorry to say it hasnt solved the issue of the belt being to tight. the flywheel is now spinning the right way and the gears are in the going in the right direction but the belt is still to tight for clutch to disengage. got me thinking perhaps the original belt was to short and so the new belt is too. the belt came with the tractor when i bought it but was not fitted so its possible its not the original.

[Austin]

Now it’s been a little while since I’ve messed with my 728. But from memory a wire running to the throttle/choke bracket on the side of the engine sounds right. I also believe on mine there was then another wire bolted to it that went up underneath the shroud (both bolted to the same spot), that was then the magneto kill wire. Now don’t take my word completely for that, but that’s my memory from working on mine. I can get some pictures next time I’m in the shop.

[MinionKing]

6 minutes ago, Austin said:

Now it’s been a little while since I’ve messed with my 728. But from memory a wire running to the throttle/choke bracket on the side of the engine sounds right. I also believe on mine there was then another wire bolted to it that went up underneath the shroud (both bolted to the same spot), that was then the magneto kill wire. Now don’t take my word completely for that, but that’s my memory from working on mine. I can get some pictures next time I’m in the shop.

As it happens Austin I think your 100% right, when I popped down the workshop an hour ago to double check what was a rather silly mistake I checked that wire while I was at it. There is indeed a 2nd wire running up to the magneto from that earth bolt and it appears there is a break in that wire as it runs up under the shroud. ive not yet repaired it but i suspect your right in that being the kill wire. will find out tomorrow 

[Chris727]

To download a parts and operator's manual, use 990577 or 990765 as y our MFR number. The first number is an early 728 and the second is a late 728.

 

[MinionKing]

17 hours ago, Chris727 said:

To download a parts and operator's manual, use 990577 or 990765 as y our MFR number. The first number is an early 728 and the second is a late 728.

 

thankyou for this Chris  this has proven to be a huge help. ive now found the correct parts manual for the tractor and found that I seem to have a number of parts missing. 2 belt stops at the front pulley, and a spring at the end of the clutch bar as it joins the pulley. while i think of it would anyone happen to know the diameter of the clutch pulley ? 

[MinionKing]

had a productive afternoon, thankyou all for your guidance, got the clutch working as it should be, belt is now the correct tension (wrong pulley installed) although still sticks occasionally.

managed to free up the selector fork for 2nd & 3rd gear and was able to drive it for about 10 minutes before the gear selector jumped the forks again. couldn't free it up this time so looks like ill have to strip the gearbox down.

[MinionKing]

update, pulled the gearbox apart and found the selector fork for 2nd & 3rd has disintegrated into 100 little pieces 🤣 starting to wonder if this tractor is worth the effort.

[SmilinSam]

On 7/4/2024 at 3:22 PM, MinionKing said:

I seem to have a number of parts missing. 2 belt stops at the front pulley

The belt stops are critical to having the tractor clutch system work. If they are missing, or out of adjustment the clutch system will not properly work.

1 hour ago, MinionKing said:

🤣 starting to wonder if this tractor is worth the effort.

One could always keep an eye out for a dead tractor with a better transmission. Those little 3 speeds were found in alot of different models across the years. Broadmoors 728 & 738, a couple of Yeoman models, the system series lawn tractors, and even up into the 4000/5000/6000 series tractors.

Edited July 6, 2024 by SmilinSam

[Mikeac]

Might have nos shift fork if interested