Hi, I've scoured the postings and found many people with similar problems but only 1 or 2 with identical problems to mine. I have a Toro Timecutter 14-38Z (model 74301 serial 230004085) zero turn mower with a Briggs %26 Stratton 14HP OHV engine (model 280H07-0166-E1) and it only has about 120 hours of use from new, although it was stored for past years while I relocated to New Jersey (drained of gas)

After checking oil and fluids, putting in new battery, cleaning the air filter(s), and changing fuel filter and lines, the mower started right up.

After a couple of hours use, the engine started to strain under load. At first I noticed the hydrostatic drive was straining at full throttle. Upon engaging the blades, I could hear that they took a while to spin up. I had problems cutting the grass, and mower was choking on the grass. If I went up a slight incline, the whole mower started to vibrate/ shake.

I first took apart the carb , and cleaned thoroughly with carb cleaner and compressor. I also checked the hydro drive for obstructions, and sharpened the blades and greased the bearings and wheels to ensure it was as efficient a cutting machine as possible. The carb had no buildup and the solenoid was working fine. The plug was not fouled, and had a light coating of emissions, but dry of oil, and sparking strong.

If I disengaged the hydro and the blades, the engine seemed to idle fine, but the tappets were rattling, and the engine didn't increase rpm after about 2/3 of max. Instead, I heard a dull popping sound.

Last weekend, I adjusted the valves to within tolerance (0.004" intake and 0.006" for exhaust), and checked for a partially sheared key (key was fine). Valves had some slop, but not much, and engine always started easily. Still no improvement in power !

After taking the valve cover off again, and turning the flywheel by hand, I noticed that the exhaust valve has a good amount of travel, but the intake valve is hardly moving. I notice it has two movements. One almost undetectable straight after the exhaust stroke, and one again on the next stroke, but nothing like exhaust. I checked that the valve springs had good travel, and they both did, so nothing binding the valves.

I finally took the intake push rod out thinking it must be broken or bent, and it was perfect. I could roll it on the garage floor and it was perfectly straight.

After lifting off the head, and holding the intake push rod in by hand and turning the engine (quite tricky with oily hands!), I noticed very little movement on the push rod, maybe an 1/8".

I've heard of people saying that there was a heat treating issue on intake cam lobes on B%26S OHV engines thus leading to premature cam lobe wear. Could it be this or could the tappet valve at the bottom of the push rod (making contact with the cam lobe) have been worn/disintegrated?

If so, before I begin the larger task of lifting the engine out of the mower to access the crank case, is there another way of verifying I need a new cam shaft or the lesser tappet valve?

There's a lot of collateral to remove from the engine before I could lift it out, especially on a hydrostatic drive mower, but am willing to do this if I have to.

Apart from a bad camshaft, what else could cause this premature loss of power?


Finally, the zero turn is pulling slightly to the right, and not sure if that is related to lack of engine power (not giving enough to each differential) or another problem?

Your diagnosis on other posts has been very very helpful in getting this far, and I thought that the valve adjustment would have done it, but alas I'm having to turn to you experts to get a resolution. Getting this to a shop to repair would be crushing, especially since I've been unemployed for 9 months and fixing everything in my house (since time is what I have).

Please let me know. If I need to order parts, I'd rather do it today or tomorrow so I have a decent shot of getting this fixed before my next mowing. I ended up using the walk behind Honda and sharing this duty with my wife to cover the 0.80 acre lot and it was 90 degrees.


Thanks in advance and best regards

Hi,
The bad cams were more common on the 31 cu. in. engines, but could occur elsewhere.
The new kit should be part# 790400 and include new tappets.
Peace,
Clarke

Thanks Clarke for your response and information on the kit. I plan to tear down the mower tomorrow afternoon, and hopefully find a worn or damaged tappet, but if it does turn out to be the camshaft, then I will have to order the entire kit, crankcase gasket, head gasket and rocker cover gasket set. Either way, the tear down is extensive at this point. I will follow up with a post once I'm complete. Best. K

Just a couple of things:
Fuel pump?
Improper adjustment of valves. Is it done at 1/4" after top dead center on this engine? e.g. Using a dial indicator to find the position of the piston?

PS: Very informative post

Hi,
It will be the lobe of the cam. No tappet problems have ever been reported. Cam problems were, however. Improper heat-treating and the new one will not look like the old one.
Peace,
Clarke

Hi All, especially crigby and KeepItSimpleStupid,

BTW - there is no fuel pump on this model. It's gravity fed.
Okay, here's the update. I managed to get the engine out of the bay today after first removing blade belts, hydro belts, PTO clutch assembly, carb, cables etc.

Taking off the sump cover/ crank case cover, I peered inside and could immediately see the exhaust cam lobe touching the cam follower. When I looked at the other cam lobe, it was almost circular ! Pulling the camshaft out and examining, I was floored ! There was hardly any indication that the cam was EVER an oval, as it looked round. I could see minimal burring on the edge, but other that that nothing. I had changed oil after my initial problems started happening 2 weekends ago, and the old oil looked dark, but it was almost a full 48 oz load, so it never got low. The new oil I drained before tearing the engine was golden, BUT there was graphite like sludge at the bottom of the crank case and crank cover. So my cam lobe must have been made of #2 pencil lead !

I've taken plenty of pictures if anyone ever wants to see a worn cam shaft, but have no way of posting to this thread. I may try putting them up on my MobileMe site and list the url for you guys.

Thanks for the prompt and accurate responses. You guys rock. I'll order parts tomorrow (or try my local lawn mower repair place to see if they carry), and assemble as soon as I get them. In the meantime, I'll clean the thing up while it's on my garage floor.

Crigby - You say the new one will not look the same. Is it milled out of solid piece or just different?

Lastly - The engine speed governor device isn't exactly obvious to put back - Any pointers? Torq settings on crank and head bolts? Is 15 ft/lbs? Any particular order ?

You can post directly using "Go advanced/Manage attachments" If you need to re-size the images, you can use the free program IrfanView - Official Homepage - one of the most popular viewers worldwide (http://www.irfanview.com) Putting 640 in the highest pixel dimension usually works.

Here's the pictures thanks to KeepItSimpleStupid who pointed out I could post. Hope it helps others.

Wow! Where did the CAM go!

Thank you both for the info and pointers. .

I called the Toro dealer I purchased this from today (in Palatine, IL) and asked him if he had any other Toro TimeCutter's with this engine come back with a worn cam lobe and he said he hadn't. He hadn't had ANY B&S engine come back with this, but he admitted that wasn't conclusive, since he only sold 10 Timecutters (He's a big fan of Simplicity).

Anyway, after hearing the story, he strongly advised me to call Briggs as he said they stand behind the product and would make an exception if you made a good case (which he admitted this was). He said that he had even stopped enquiring about warranties on Briggs stuff since Briggs had over ruled him several times and sided with the customer.

I did call B&S this afternoon and they've opened a case and a product specialist will call me in a couple of days. ("it's their busy season"). The gentlemen on the phone said he hadn't heard of the heat treatment problem but that he wasn't an authority. He advised I wait for them to call me back before proceeding with purchase of replacement parts.

Nice!

Hi,
Unfortunately for your excellent observation abilities have already told you it is the cam since noe rocker moves about a half inch and the other barely moves. Never seen a bad tappet! I am sure it is possible, but the cam problem is wll documented.
Peace,
Clarke

Last update and closure ! I finally received a call from B&S product specialist (they didn't escalate internally for about a week so it got delayed). He read my history and immediately said he had no problem providing me with a new cam shaft, if I took the old cam to my authorized dealer for evaluation. I told him I moved state and he said this was no problem. I then asked him for a set of engine gaskets as well, and after a pause, agreed to that also. I know he saw the sense in this, since I really shouldn't have my $2800 zero turn in pieces on the floor for 3 weeks because of a catastrophic engine failure after only 100 hrs of use. I let him know that I appreciated Briggs standing behind their products and would let others know this fact.

I called my local B&S dealer and they were caught off guard a little since I didn't have an RMA number, but I gave them the name and direct phone number of the product specialist (who encouraged me to do so in case of any doubt), and told them to check it out. They did so, and then placed the order for the spares.

Once I got the cam on Friday, I began the rebuild on Saturday. Had it in the engine and rebuilt in about 2 hours, but then began to take my hydro out to check the oil levels. That was a not straight forward and required some jiggery pokery. Who tightens T30 bolts to over 100ft/lbs ? Yes 100 foot pounds !

Anyway, finally got the hydro out and wouldn't you believe it, the oil was perfect ! Well, now I know for sure.

Took me about another 4 hours to get everything back on the mower.

The mower started first time and ran very very strong. I had to adjust the carb linkages and governor but it was perfectly smooth and I have all my power back. The blades are running at an amazing speed now and the grass has no chance. I ran for about 2 hours yesterday, with a cooling break every 20 minutes or so, and I will change the oil again this weekend just to get rid of the "broken" in camshaft sediment.

Thanks for helping me get to the resolution, and just goes to show that Briggs does have pride in their products and will stand behind them one you prove your case.

Last update and closure ! I finally received a call from B&S product specialist (they didn't escalate internally for about a week so it got delayed). He read my history and immediately said he had no problem providing me with a new cam shaft, if I took the old cam to my authorized dealer for evaluation. I told him I moved state and he said this was no problem. I then asked him for a set of engine gaskets as well, and after a pause, agreed to that also. I know he saw the sense in this, since I really shouldn't have my $2800 zero turn in pieces on the floor for 3 weeks because of a catastrophic engine failure after only 100 hrs of use. I let him know that I appreciated Briggs standing behind their products and would let others know this fact.

I called my local B&S dealer and they were caught off guard a little since I didn't have an RMA number, but I gave them the name and direct phone number of the product specialist (who encouraged me to do so in case of any doubt), and told them to check it out. They did so, and then placed the order for the spares.

Once I got the cam on Friday, I began the rebuild on Saturday. Had it in the engine and rebuilt in about 2 hours, but then began to take my hydro out to check the oil levels. That was a not straight forward and required some jiggery pokery. Who tightens T30 bolts to over 100ft/lbs ? Yes 100 foot pounds !

Anyway, finally got the hydro out and wouldn't you believe it, the oil was perfect ! Well, now I know for sure.

Took me about another 4 hours to get everything back on the mower.

The mower started first time and ran very very strong. I had to adjust the carb linkages and governor but it was perfectly smooth and I have all my power back. The blades are running at an amazing speed now and the grass has no chance. I ran for about 2 hours yesterday, with a cooling break every 20 minutes or so, and I will change the oil again this weekend just to get rid of the "broken" in camshaft sediment.

Thanks for helping me get to the resolution, and just goes to show that Briggs does have pride in their products and will stand behind them one you prove your case.

Could it be the compression release arm that's scoring the lifter, causing the cams lobe to fail ? Funny that the bottom lobe would go first, seems it would have the best chance at getting oil.

Could it be the compression release arm that's scoring the lifter, causing the cams lobe to fail ? Funny that the bottom lobe would go first, seems it would have the best chance at getting oil.

Thanks for your input but please note the original post was in 2010.

I found this post/topic helpful 5/6/15 and might spark new/old interests, and new, well experienced answers ? Knowing the real reason the cam failed, so if I tackle this job and there is a trick out there from preventing me from doing this miserable repair again EVER. I would appreciate constructive replies. You knowJay