The Jack's Small Engines Forum - Join Our Online Community
Jacks Small Engines Lawn Mower & Power Equipment Forums
Community Stats
1 day 7 days 30 days Max. View More
Top Posters
  1. SRTsFZ6
    (106 Recent Posts)
  2. doug2500
    (11 Recent Posts)
  3. Jchaps20
    (10 Recent Posts)
Most Active Threads
  1. The mounting bolts shrank- Briggs mower carburetor reinstallment
    (21 Replies)
  2. Briggs 21 HP Single Cylinder. Bad rings?
    (20 Replies)
  3. Compression Release on FS111R Trimmer not working
    (17 Replies)
Top Rated Posts
    There is no record available at this moment
Birthdays
There is no record available at this moment
2019/07/07 18:50:28
Ngrepke

Fix or Replace Briggs Twin

Hello! I am brand new to this forum and I am looking for some advice. I am a DIYer with very basic engine knowledge.
 
Here is the deal. We have a 50" Cub Cadet Zero Turn. It has a Briggs and Stratton Twin Model 407577 Type 0317-E1 Code 040402YG.
 
From the time we took ownership of it over four years ago it had a fair amount of oil residue at the engine base that seemed like it might be from the valve covers. It would start ok, but always smoked a little on startup. As it got more worn it would smoke a little as it ran. It would always backfire when it was turned off after running a little. Well my wife was mowing and it lost power and quit. When I went to try to start it, it sort of made a popping sound as it cranked but wouldn't start. So I tore into it this weekend. I started by taking the valve covers off and right away I could see a problem. The Push Rod on the exhaust valve is broken. In the intake appears intact. I checked out the other side and all seems normal at least at a glance. Next I removed the spark plugs to see if the pistons were actuating as they should, they did. So I removed the engine and flipped it over to remove the pan. Once I got into the bottom and rotated the cam shaft, everything was moving as I think it ought to.
 
Now I've considered two things. Do a rebuild on this engine or buy a predator from Harbor Freight to put in it. If I can get buy by replacing a couple things and getting this engine happy again, I'd like to. That said, would anyone ever just put a new push rod in and replace some gaskets and put this back together? Would it be wise or required to do more? Would that push rod failure be an indication of some other issues?
 
I clearly do not know what I do not know. I really appreciate anyone who is willing to offer me some advice and direction. Thank you!
 
 
28 comments Leave a comment
Roy
First of all, welcome aboard! The push rod likely failed because the valve guide walked out of the bore and contacted the valve retainer. Often the result of overheating. Remove the bblower housing, the cooling fins could be clogged with grass.
The guides are not serviceable, Briggs says replace the head. A machine shop may be able to knurl the guide so it can be pressed in and stay put. While the head is off  check the sump gasket, it may be leaking which is common. You will need to remove the engine and follow the factory instructions to repair it.
2019/07/07 21:34:49
AVB
I believe if you look very close at the on the side that broke the push rod you will find the valve guide has moved out position to a point that the valve can no longer travel it full travel. IF so replace the head, push rod, and gaskets. Also open up the crankcase and find the other piece of the broken push rod. From there you should be good to go.
 
Just a side note the heads are currently on back order from Briggs. I am awaiting a pair currently myself for a customer.
2019/07/07 21:38:41
Ngrepke
Thank you both very much for the welcome and response. I have the engine out and the engine opened up. I shot a quick video you can see at this link.[tube]https://youtu.be/PQt7ULLs0ao[/tube] And I found the other half of the push rod. Based on my video (If I need to do another let me know) does this confirm what you both are saying. Replace the head, push rod, and gaskets? Do the heads only come in pairs?
 
THANK YOU!
2019/07/07 22:06:37
Roy
The heads are sold individually but you need to specify which one you need. #1 is closest to the flywheel.
2019/07/08 11:58:19
Ngrepke
Ok, how do I ultimately determine if I need a new head? Is a visual inspection going to tell me? Or do I need a measuring tool? Or is it a feel sort of thing? Or does a broken rod automatically require a new head?
 
Thank you!
2019/07/08 13:37:38
AVB
Roy
The heads are sold individually but you need to specify which one you need. #1 is closest to the flywheel.

You would think so but according to Power distributors they are sold as a set.
 
From Power Distributors order entry page.
BS, 597562 HEAD, CYLINDER
Package Notes: CONTAINS CYLINDER HEADS 1 AND 2
Part Notes: Supersedes from BS, 792300
 
Which this would include the 792299 head too.
2019/07/08 13:51:41
AVB
As how to check it is easy when comparing to the intake valve guide position with just the valve cover off.
 
2019/07/08 13:53:22
Roy
What a crock!! What is he to do with a perfectly serviceable spare head?
2019/07/08 19:51:23
AVB
Roy
What a crock!! What is he to do with a perfectly serviceable spare head?

I have the same problem. All I need is cyl 2 and I am out $116 for both heads. Well there might be reason that I currently don't know of until I get them in as they may have one slip of paper indicating why the two are needed.
 
What worst they are currently on back order until at least July 15. Of they told me about the same time frame on four vacuum hoses I needed and they have been on back order for two months now. I just cancelled the coil I was needing and ordered an aftermarket replacement. It was on back order for over 30 days.
 
About all he can do is sale it at half of what he pays for both on eBay as someone may need the unused head. That probably what I will do with cyl 1 head; unless, there is a reason I need to install it.
2019/07/08 20:19:31
Ngrepke
I am thinking of trying a fix versus replace. I found some other ideas and I’m pursuing pushing the seal back down and having a mig welder tack a bead so it can’t slide out. Hoping to save a little and not wait on the back order. Only decision now is whether to do the other side while I’m at it.
2019/07/08 22:42:10
Ngrepke
I took the second head off to inspect and I am wondering if the valve seal has shifted on it. Does anyone know how far out the seal should be protruding. It is out around 3/16". Thanks all!
2019/07/10 09:40:31
Roy
Look at the guide, if there is a shiny ring above the top of the bore in the head it has moved.
2019/07/10 11:58:44
Ngrepke
Well I got everything put back together. I was lucky to have access to a parts cleaner and putting everything back together clean was really fun. I was careful. I followed the torque specs and instructions. Everything was pretty smooth. The muffler is in pretty bad shape and so one mistake I made was to start the engine with the muffler off. It sounded mean :) I shut it down and installed the muffler. Its much better sounding now. I have two concerns. First a backfire after shutdown. The mower has always backfired when you turn it off after running for a while. I had hoped it was related to the valves and that my work would have resolved it. Not the case. Could it be the valves are needing further adjustment? Could it be a worn lobe on the Camshaft preventing the push of the valve far enough? (Wish I had inspected that while I had it all apart). Could it be related to the carburetor? Secondly the high speed on the engine after the reassembly sounds slower. And the throttle movement travels far without affecting engine idle. More than I remember from before. That seems to me to be a cable or governor adjustment. How do I know when I have it dialed in or even how to tweak it? Just by ear, or is there a more technical way?
 
Thanks for all the help guys. We are at least operational again!
2019/07/15 16:21:32
Roy
It sounds like the governor spring is not correctly installed. Can you post a picture(s) of your linkage?
2019/07/15 21:08:53
Ngrepke
Here are some photos.
2019/07/15 21:21:49
Ngrepke
Those pics aren't very telling are they. It's seemingly impossible to find the camera angle where you can see the springs. 
2019/07/17 10:12:43
Ngrepke
I revisited the governor setup and everything looked correct based on videos and pictures I reviewed. The throttle cable seemed to be slightly out of adjustment so I made a tweak there and sent my wife out to mow. Then two new things developed. 1st, (we have a 50" cub cadet zero turn) my wife shut off the deck to cross our gravel driveway. Once she reached the other side the deck would not come on. Rewind a few weeks, before the engine issues, the PTO switch failed. I put a new one in and that solved it. So I am wondering if the PTO switch could have died again so soon? Well while troubleshooting the PTO switch the mower now will not start. It made me think that perhaps the PTO issues are telling the engine not to start. I don't know enough about this machine to know what safety sensors allow the starter to turn but the engine not to start. In other words, I'm wondering if I should be trouble shooting an engine issue AND a PTO issue, or if all things are related to a sensor that has failed. I'm sitting stumped.
2019/07/21 14:02:14
AVB
It could be very possible the PTO switch has failed again due excessive drawn by the electric clutch's coil. These clutch can still operate even they are partially shorted. Normally they pull no more 7 amps max but closer to 3 amps is an average I see here. Now I have seen these electric clutches to be pulling nearly 20 amps and still work but this burns up switches since they not design to operate above 10 amps. I even seen connectors to be melted because of this excess current.
 
If you have an Ohm meter handy check the electric clutch coil's resistance it should be no less than 1.7 ohms.
 
Many mower OEM don't even fuse this circuit though I do on any repairs I do to the PTO circuit by adding a 7 amp fuse as a safety.
2019/07/21 16:53:21
Ngrepke
AVB,
 
Thank you for the suggestion. I checked the clutch and I was getting 0.1-1.3
I am still very stumped. Maybe this means the clutch is shot, but I also cannot get the engine to start. So I am wondering if I am battling two issues or one. The PTO switch tested out ok. Clutch might be shorted out. Engine has compression. Engine has spark. Engine is getting fuel. What am I missing? What do I check next?
 
Thanks!
2019/07/22 22:24:25
AVB
Check the fuel solenoid on the bottom of the carburetor for proper operation. Should be clicking when you turn on ignition switch. You might need to remove it and check that the rubber tip hasn't come off and is now blocking the main jet constantly.
 
For some reason I had three solenoids to do this in the last month with this type of rubber tip.
 
An expensive little monster even with my dealer discount.
2019/07/23 08:18:07
Ngrepke
I took the carb off and removed the bowl. The solenoid plunger moves freely and the rubber tip is still intact. I plugged the wire harness back in and put the key in run position. I expected the plunger to go down, it did not. So the I checked voltage at the harness at I getting 12v. So....it seems the solenoid is bad. I’ve seen others remove it grind the plunger. Is that a terrible idea? Thanks!
2019/07/23 21:42:52
Ngrepke
Ok, one mystery solved! The no start was in fact the fuel solenoid. I broke off the plunger just to see if I could get the engine to start. And wham, it fired right up. I now wonder if I should go forward with ordering a new fuel solenoid or if I can run the way I am. I could add a fuel line shut off between the fuel pump and carb, or is that bad hack? Next I need to figure out why the PTO wont engage. I checked ohms on the clutch again and it still only gives me between .7 and 1.0. I am thinking that means its bad. So I am about to look at what a new one costs...gulp. The dang mower is nickel and dim'ing me! Can a clutch be rebuilt? Thanks for hanging with me all!
2019/07/23 22:21:05
Roy
Nipping the solenoid will work fine, it is only there to avoid a loud bang on shutdown scaring the dog. It does not control a flooding situation, that is the inlet needle's job. Do you have power to the clutch? Your resistance sounds ok. Make sure it is grounded.
2019/07/23 22:57:14
Ngrepke
Roy, thanks for the response the mower before all the work always backfired terribly, so my wife, kids, and dogs are all used to it :) I thought I needed 2-4 ohms for the PTO? I checked the switch, but come to think of it, I have not checked the leads to the clutch. I will now!
2019/07/23 23:00:33
Ngrepke
Roy, confirmed. 12v coming from the switch that is engaged with the key in run mode. It was getting juice. I think its dead. Do you concur?
2019/07/23 23:08:12
AVB
Roy
Do you have power to the clutch? Your resistance sounds ok. Make sure it is grounded.

Roy these electric PTO are partially shorted if .7 - 1.0 ohms. Warner has the minimum resistance reading at 1.7 ohms. And if the max current allowed at 12 vdc is 5 amps then a good reading would be 2.4 ohms. Many mowers that have a fused PTO clutch uses a 7.5 amps fuse so at charging voltage of 14.8 then minimum ohms allowed is 1.97. ON these mowers if the clutch coil is down to 1.7 it would be blowing the fuse as it would be pulling 8.7 amps.
 
Ngreke provided you are  reading this across both wires at the solenoid then yes the solenoid is dead. And since most handheld Dvmm and analog meters seldom read directly anything over 10 amps it is best to either use a clamp meter or simply install an inline fuse and install a 7.5 amp fuse. If it blows the fuse when the PTO is turned on replace the clutch assembly. An line fuse also saves the PTO switch, ignition switch, wiring, and any other electrical components associated with the PTO from excessive current.
 
2019/07/24 08:21:00
Ngrepke
AVB. Thanks so much for the tip on the fuel solenoid. You restored my confidence and got me back on track. Thanks!
2019/07/26 20:00:23
Ngrepke
The cub cadet is mowing again. Snipped fuel solenoid plunger and replaced the PTO clutch. Hoping repairs last a while!
2019/07/26 20:01:41

Comments are closed.

Copyright © 1994 - 2016 Jacks Small Engine & Generator Service, LLC
© 2025 APG vNext Trial Version 5.5