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Changing parts to determine why an engine is not working properly can get expensive fast.
Time is worth money, too.
At $80 an hour even diagnostic work gets expensive.
Once we value our time it gives us perspective in terms of whether we want to diagnose, or just replace.

Remember that only 3 basics needed to run many gas engines
Combustion air
Gas
Spark
Removing any of these 3 and u will have a none running engine
Yeah but this one runs, it just cuts off once it's warmed up and the operator engages the PTO or the forward/reverse hydraulics... So the first step here would be to test the coils, come to think of it maybe the seat safety switch.
 

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Time is worth money, too.
At $80 an hour even diagnostic work gets expensive.
Once we value our time it gives us perspective in terms of whether we want to diagnose, or just replace.



Yeah but this one runs, it just cuts off once it's warmed up and the operator engages the PTO or the forward/reverse hydraulics... So the first step here would be to test the coils, come to think of it maybe the seat safety switch.
You sure don’t follow threads very well.
His seat switch is bypassed.
He just replaced the mags.

If you are working on things yourself, you don’t pay $80/hr.
 

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Ok, I took a video after changing the coils.
Here is the link:
I think the engine runs better than before.
Mower runs at a fast pace with the PTO engaged but still dies when it warms up.
But now I notice the engine surging when warm after I restart it.
One question. WillI I hurt the engine if I run it with a bad head gasket?
Thanks,
I do believe it’s running better now too. Sounds different. How old are the spark plugs?

It kind of sounds like it’s running out of fuel, but it shouldn’t take it that long to run out. I tend to agree that something is warming up and quitting. It is entirely possible a valve(s) is sticking.

So, you ordered a compression test gauge, correct? I’d still like to know those results.

Yes, you can damage the engine running it with a blown head gasket. Plus, the engine will be low on power and thus perform poorly.

Edit: I want to apologize to you in advance for the subsequent posts #104-#117. They do not pertain to this thread, or you. I will try to stay on topic.
 

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Ok, I took a video after changing the coils.

But now I notice the engine surging when warm after I restart it.
One question. WillI I hurt the engine if I run it with a bad head gasket?
While the rear bumper is off
I would either replace the carburetor with a new one, buy the gaskets as well.
Or adjust the valves next, you'll need the valve cover gaskets:
110607013 Gasket, Rocker case

One question. WillI I hurt the engine if I run it with a bad head gasket?
It's not good for it, but you should be able to run it like you're doing for testing.
 

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While the rear bumper is off
I would either replace the carburetor with a new one, buy the gaskets as well.
Or adjust the valves next, you'll need the valve cover gaskets:
110607013 Gasket, Rocker case



It's not good for it, but you should be able to run it like you're doing for testing.
Again, he ordered a carb and gaskets. Waiting on them to arrive. But I don’t think the carb is the problem. I don’t think it’s even fuel related. Takes too long to die and start up too quick.


You just said you don't pay yourself.
Here:
J. Baker said:
If you are working on things yourself, you don’t pay $80/hr.
Correct. I don’t pay myself $80/hr to work on my own stuff.
 

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We as in everyone around here, as in WHERE I LIVE, what is the matter with you?
Whether $80 an hour or whatever, it was about valuing your time, not the actual dollar amount, step off it already.
When you aren’t a mechanic, but acting as one, your time isn’t worth much. You would have to spend a ton of time diagnosing before it would be cheaper to throw parts at anything. The more parts you throw at it that aren’t bad, the closer you come to a repair bill from someone qualified to diagnose and fix your stuff.

When I had my shop I had several customers like you. They thought they could fix their own stuff and would eventually give up and bring it in. They would tell me the problem and what all they had replaced in an attempt to fix it. Usually followed by the total cost. More often than not, my bill was LESS than their guesses and it was actually fixed. Point is, unless you diagnose, then repair, it’s usually cheaper to just pay someone to do it. A true business man realizes the point when it’s cheaper to pay for a service than to try to do something “in house”. Whether that be a repair, or subcontracting work. Any time you spend doing something that doesn’t earn you money, it’s costing you. In my case, I’m over qualified to do my own work. Often times, I can do it faster than the 5 year tech at the dealership or shop. And, I’ll do it on a rainy day, at night or over the weekend. Or in the winter like I’m doing now. I can also typically get something fixed right away without waiting to get on someone’s schedule. Not everyone has that option though, I know.

What kills me is when guys think they’re saving money throwing parts at something until it fixes it. Get on your back up mower and go mow while a shop fixes your other one. That way you keep earning money while someone else does what they know how to do. In the end, you’ll make more.

Point is, if you truly value your time, you learn to recognize where your time is best spent.
 

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Discussion Starter · #110 ·
I do believe it’s running better now too. Sounds different. How old are the spark plugs?

It kind of sounds like it’s running out of fuel, but it shouldn’t take it that long to run out. I tend to agree that something is warming up and quitting. It is entirely possible a valve(s) is sticking.

So, you ordered a compression test gauge, correct? I’d still like to know those results.

Yes, you can damage the engine running it with a blown head gasket. Plus, the engine will be low on power and thus perform poorly.

Edit: I want to apologize to you in advance for the subsequent posts #104-#117. They do not pertain to this thread, or you. I will try to stay on topic.
Good afternoon Baker.
I borrowed a compression tester and checked the compression cold ( I was going to do it with the engine warm but did not know if the cold reading would give you any useful information).
I can do the test with the warm engine if I need to.
The max pressure on the cylinder with the bad gasket is zero. The other cylinder is 80.
I guess the engine has been running on one cylinder (dang it!).
I also took a picture of the plugs. The one that looks dirtier is the one from the bad cylinder.
Automotive tire Cylinder Household hardware Gas Auto part

Thanks for not giving up on me.
 

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@cboudet
It’s still morning in my part of the world, but just barely, lol! Good afternoon to you just the same!

Well, that information certainly isn’t good, but I did fear that one cylinder was dead. It just didn’t sound right to me, but I still think it sounded better after the coils. The one on the good cylinder was probably breaking down.

So first off, thanks for the pictures of the spark plugs. That’s more helpful than you know. Also on the topic of cold compression check vs hot/warm, yes, the cold number was a good choice. Now knowing that result, no reason to do a warm check.

The bad news:
I’m really sorry to tell you, but this engine is likely a loss at this point. Zero compression on the one cylinder may be able to be easily fixed or at least improved, but 80psi on the other isn’t good. Only possible saving grace would be if you didn’t open the throttle all the way to do the compression test. Where was the throttle set when you did it? At idle? Or wide open (all the way in the “fast” position? Before I go on, maybe answer that question. If you did the test with it in idle, go test the “good” cylinder again but this time with the throttle in the “fast” position.
 

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Discussion Starter · #112 ·
@cboudet
It’s still morning in my part of the world, but just barely, lol! Good afternoon to you just the same!

Well, that information certainly isn’t good, but I did fear that one cylinder was dead. It just didn’t sound right to me, but I still think it sounded better after the coils. The one on the good cylinder was probably breaking down.

So first off, thanks for the pictures of the spark plugs. That’s more helpful than you know. Also on the topic of cold compression check vs hot/warm, yes, the cold number was a good choice. Now knowing that result, no reason to do a warm check.

The bad news:
I’m really sorry to tell you, but this engine is likely a loss at this point. Zero compression on the one cylinder may be able to be easily fixed or at least improved, but 80psi on the other isn’t good. Only possible saving grace would be if you didn’t open the throttle all the way to do the compression test. Where was the throttle set when you did it? At idle? Or wide open (all the way in the “fast” position? Before I go on, maybe answer that question. If you did the test with it in idle, go test the “good” cylinder again but this time with the throttle in the “fast” position.
No, I did it at idle. I went back and did it at wide open throttle and it only went up to 90, but I suspect it is not enough..
Maybe if I do it warm, with oil on the rings the pressure may go higher.
Thanks
 

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No, I did it at idle. I went back and did it at wide open throttle and it only went up to 90, but I suspect it is not enough..
Maybe if I do it warm, with oil on the rings the pressure may go higher.
Thanks
Well… that’s that then. I knew it wouldn’t go up much, but was hoping for at least 100 PSI. Ten PSI difference is about right.

So, here’s the deal. The good cylinder has likely been carrying the load for so long it’s worn out. If you were to try and fix this engine by addressing the dead cylinder, you will end up with too much variation in cylinder contribution, and that’s if the dead cylinder isn’t so far gone that it can come back to at least 80 or 90 psi. It’s still way too low to spend a bunch of money on it unless you do a complete overhaul. Getting the engine warm and doing another check may bring the numbers up a bit, but it’s irrelevant. Itfit can’t hit at least 100-120 psi cold, the motors life is over.

Sorry to say, but you need a new engine. Don’t waste anymore time/money on this one.

All that said, there is no oil smoke out this engine and the spark plugs don’t show signs of oil consumption, so it is possible that you could replace both heads with new and bring it back, but that’s a determination I would make upon head removal and cylinder inspection. That’s not something I’m comfortable suggesting you to do, as I would only be able to accurately determine that with my own eyes. I just can’t do it via pictures and descriptions of what you see. My professional advice is to buy a new engine or another mower.
 

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That's too bad really, seen many a good engine get thrown away over what is most likely a minor issue. I do agree throwing used parts at something broken isn't likely to produce a good fix.
Typical quick determination through notoriously inaccurate methods, yup it's toast, here buy another. Granted time is money too.
 

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I wouldn't say it's trash, alot of compression testers don't read exactly right. I've seen cheap harbor freight ones read over 40 psi lower than a different name brand one. You're trying to run on one cylinder and chase a different problem. Fix the blown head gasket first and go from there.
The dead cylinder needs a new head. Actually they both need replaced, I’m certain. But then, what is the condition of that running cylinder? He’s better off not buying anymore parts.
 

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Given the parts he has already replaced, the fact one cylinder is dead and we know that it repeatedly blows head gaskets on that cylinder means the following:

The head on the dead cylinder is warped and will not hold a gasket.

The running cylinder is overworked and overheating. The way it dies in the last video, I’m confident the valves in the “good” head are seizing and not closing. I also suspect that head is also warped. That explains the surge upon restart. The valves cool just enough after dying to move good enough to restart, but are still sticking. After combustion heat is reapplied, they seize again. Most likely the exhaust valve. I’ve seen this all before. Difficult to diagnose, but I’m confident if you removed the good head and took the valves out, you’d find them hard to remove and the exhaust valve would be black from soot at least 1/2 to 3/4 up the guide.

Then there’s the fact when he first got it, it over revved. Very likely the initial cause of the entire destruction.
 

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In years past, THIS was the time of the year that KAW can more easily sell you an FH replacement. Call around for the best price and they can ship it to your door or dealer of choice.
 

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Discussion Starter · #120 ·
Given the parts he has already replaced, the fact one cylinder is dead and we know that it repeatedly blows head gaskets on that cylinder means the following:

The head on the dead cylinder is warped and will not hold a gasket.

The running cylinder is overworked and overheating. The way it dies in the last video, I’m confident the valves in the “good” head are seizing and not closing. I also suspect that head is also warped. That explains the surge upon restart. The valves cool just enough after dying to move good enough to restart, but are still sticking. After combustion heat is reapplied, they seize again. Most likely the exhaust valve. I’ve seen this all before. Difficult to diagnose, but I’m confident if you removed the good head and took the valves out, you’d find them hard to remove and the exhaust valve would be black from soot at least 1/2 to 3/4 up the guide.

Then there’s the fact when he first got it, it over revved. Very likely the initial cause of the entire destruction.
Good morning Baker.
I decided to follow your advise and will probably be getting a new mower.
I also decided that I want to learn a little more and I will be continuing to play with the old engine.
I don't know if you remember that I have a second engine with a good running top end, so I would like to keep this thread open and occasionally come back to it with a question as I work on the engine.
I also wanted to ask you about the compression test. You said you would prefer if the reading was around 100. I was reading the manual and think the minimum acceptable pressure on that engine is 60 psi.
I am attaching a page of the manual.
Please comment on it.
Thanks for everything!
Font Recipe Parallel Paper Paper product
 
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