Briggs & Stratton 4.0 HP Tiller Issues

[TXCarGeek]

With all this recent free time, I decided to till up some areas of my yard to lay down new sod; I recently got a hold of an old school Briggs powered tiller with 4 HP. Had no spark so I purchased a modern coil that doesn't use the points and contacts. I also cleaned out the fuel tank and cleaned and refreshed the carb with a rebuild kit. Slapped everything back together and got it cranking and running for a few seconds. Need to fiddle with the carb some more, but at some point the engine seemed like it locked up. I took off the rope/string crank to turn the flywheel by hand and it does turn but it stops after it looks like it does a full cycle...when I turn the flywheel by hand both directions, it stops.

I'm fairly new to tinkering with small engines so any help is very much appreciated.

 

[vw7674]

my not-so-educated guess would be check the new pointless ignition coil isn't grabbing the flywheel as it encounters the flywheel magnets as they pass by.
The ignition coil has to be fastened TIGHT to prevent that.
edit: .030" gap between coil armature & flywheel, I usually use a couple feeler gauges........

 

[Dinoburner]

Set the clearance of coil to flywheel to factory spec. In lieu of spec set clearance to between .005 to .010 of an inch.

 

[samven]

Have you pulled the spark plug and tried turning it over. I had a float needle go real bad and it flooded the cylinder with liquid fuel which as you know wont compress. When I pulled the plug and turned it over gas came spewing out. After I got it cleaned out again ( the carb) it mostly works OK but I had to put a fuel shutoff in line because if I let it sit for a week or so I would get fuel in the oil and the same lock up problem. I have been meaning to get a new carb for the last 3 years but it works the way it is and I never think about it until I need it again. It may be a heavy float or scared needle seat but a new float and seat cost about the same as a Chinese carb.

 

[ctechbob]

Ages ago I'd read or heard that a business card will do in a pinch for setting the distance between the flywheel and coil. Used it on my old Briggs twin back when I had to swap the coil and it worked fine. Then something else broke on the mower and I got rid of it, but it ran great.

 

[TXCarGeek]

Originally Posted by vw7674
my not-so-educated guess would be check the new pointless ignition coil isn't grabbing the flywheel as it encounters the flywheel magnets as they pass by.
The ignition coil has to be fastened TIGHT to prevent that.
edit: .030" gap between coil armature & flywheel, I usually use a couple feeler gauges........


Just unscrewed the coil and lifted it out of the way to spin the flywheel and still catches. My dad knows how to tinker on these small engines so we're going to check things out on it tomorrow.

 

[TXCarGeek]

Originally Posted by samven
Have you pulled the spark plug and tried turning it over. I had a float needle go real bad and it flooded the cylinder with liquid fuel which as you know wont compress. When I pulled the plug and turned it over gas came spewing out. After I got it cleaned out again ( the carb) it mostly works OK but I had to put a fuel shutoff in line because if I let it sit for a week or so I would get fuel in the oil and the same lock up problem. I have been meaning to get a new carb for the last 3 years but it works the way it is and I never think about it until I need it again. It may be a heavy float or scared needle seat but a new float and seat cost about the same as a Chinese carb.


Yeah, I pulled the plug to check for any obvious signs of damage in the chamber...wasn't flooded or anything. This engine had been sitting for a really long time before I started messing with it so I'm wondering if there's corrosion on the crank journals or in the lower portions of the cylinder that I can't see that are causing it to hang up. If need be, my dad and I will strip down the engine and see what we find.

 

[TXCarGeek]

Originally Posted by ctechbob
Ages ago I'd read or heard that a business card will do in a pinch for setting the distance between the flywheel and coil. Used it on my old Briggs twin back when I had to swap the coil and it worked fine. Then something else broke on the mower and I got rid of it, but it ran great.


The new coil came with an instruction card and it said to use the card to gap it...i'd say it's about the same thickness of a business card.

 

[ripcord]

Lots of times old power equipment is parked in the shed when something starts to go wrong. Hope that's not the case for you.

Does it feel like you have any compression at all? Sometimes the exhaust valve seat will come loose from the block and prevent the valve from closing all the way. Especially if it's been overheated. If you find that's the case, you can stake the seat back in with a punch and a lot of times be good to go for a long time afterwards. It might be a broken rod, but usually, you'd know if something that catastrophic had happened. Best of luck!

 

[BigCahuna]

My experience with gas powered things has been, when you find something that's been stored for a while or even years, there's a mechanical problem with it. If your lucky it might just need a carb cleanup. I had a mower that ran good after a carb redu, but the blade shaft was bent. If the frame is good on the tiller, I would either look for a used motor the replace what you have, or buy a new one from Harbor freight . The thing with tilllers is they get used so little, not really worth sinking alot of cash into fixing an old one.,,

 

[Lubener]

Originally Posted by vw7674
my not-so-educated guess would be check the new pointless ignition coil isn't grabbing the flywheel as it encounters the flywheel magnets as they pass by.
The ignition coil has to be fastened TIGHT to prevent that.
edit: .030" gap between coil armature & flywheel, I usually use a couple feeler gauges........

.030 is the spark gap. Magnetos usually are set for .007-.01 gap from flywheel . Too bad he put all that work and money in it. I would bet a few swipes on the points with emory cloth would have brought the spark back. Very common when engines sit a long time with the points open.

 

[TXCarGeek]

My dad pulled the head on it today and the bore was scored up badly in one spot. Looks like the aluminum was scraped and allowed it to build up at the bottom of the scrape...when the piston makes contact with that high spot, it gets jammed up. I'm thinking we'll look for another block and refresh some other components that may need it.

I'm wondering If I should have sprayed some sort of lubricant in the bore before trying to get it running. It ran for about 10 seconds at one point and it sounded fine. Soon after, that issue popped up.

 

[TXCarGeek]

If need be, could I just purchase a modern, horizontal shaft engine from some place like harbor freight and slap that puppy in?

 

[Lubener]

Originally Posted by TXCarGeek
If need be, could I just purchase a modern, horizontal shaft engine from some place like harbor freight and slap that puppy in?

Yes. Mounting may have to be altered.

 

[TXCarGeek]

Originally Posted by Lubener
Originally Posted by TXCarGeek
If need be, could I just purchase a modern, horizontal shaft engine from some place like harbor freight and slap that puppy in?

Yes. Mounting may have to be altered.


May have to look in to that. The tiller project is on hold for now as I'm in process of installing some bilstein leveling struts and four new control arms on my '08 Silverado 1500. Was hoping it would be quicker than it's going right now, but both front rotors were seized to the hub and I had to run to Lowe's twice for some hardware and that ate up a bunch of time.

 

[dlundblad]

Is it the ball clutch starter? I have this issue on a similar vintage Briggs on my tiller. Sadly a simple swap won't be so easy for me since it's a twin crank design.

 

[TXCarGeek]

Originally Posted by dlundblad
Is it the ball clutch starter? I have this issue on a similar vintage Briggs on my tiller. Sadly a simple swap won't be so easy for me since it's a twin crank design.


I think it might be.

 

[dlundblad]

Originally Posted by TXCarGeek
Originally Posted by dlundblad
Is it the ball clutch starter? I have this issue on a similar vintage Briggs on my tiller. Sadly a simple swap won't be so easy for me since it's a twin crank design.


I think it might be.


Not exactly the safest thing to do, but if you remove the rope starter while it's running that should give you the answer. Mine has 3 bolts. I just have them snug and buzzed them off after I started it.

Don't wear any loose clothing or jewelry. Lol