Murray engine troubles

[handirifle]

bob,
mornin,
Well, for one, mowers that have 20hp or more around here, are rare as hens teeth, Usually when they do show up they're about half the new cost, or $1200-1500, so even if this engine crapped out again, and I put a new engine on it, I am still out the same money, and I know what I already have.

Currently, I believe, all it needs is either a carb overhaul or a fuel pump (same place) so if I do that AND the valve repair holds for a season, it will help me save for a new mower. I have set my sights on the 26hp Husqy with the manufactured deck.

 

[MrFoPow]

bob,
mornin,
Well, for one, mowers that have 20hp or more around here, are rare as hens teeth, Usually when they do show up they're about half the new cost, or $1200-1500, so even if this engine crapped out again, and I put a new engine on it, I am still out the same money, and I know what I already have.

Currently, I believe, all it needs is either a carb overhaul or a fuel pump (same place) so if I do that AND the valve repair holds for a season, it will help me save for a new mower. I have set my sights on the 26hp Husqy with the manufactured deck.

What do you like in the Husq?

I'm genuinely interested because I looked at both today, and went with the Cub Garden Tractor.

 

[handirifle]

Well the 26hp one, is the one I was interested in. One item is the kawasaki engine. Smoother and quieter than others. A three rear front to back warranty. The rear tires are large enough to provide enough square footage of surface to keep it from sinking in in the marsh I call my property.

The mower deck is a manufactured deck, not a stamped one so it will stand up to all the 2" oak limbs I don't see in the 12" grass.

There's a local dealer, that has a good reputation for service.

That's about all I can come up with, but it's enough for me.

 

[handirifle]

She Runs!!!

Well, I got the carb kit in the mail Saturday, and installed just the fuel pump part of it today. I didn't rebuild the whole carb cause you have to understand my history with carbs. It's not a pretty one.

Soooo, I put the fuel pump back together, and after a few false starts to prime the carb back, it purred like a kitten. It idles very smooth and runs smooth at all throttle positions.

Now hopefully, a year from now, I can say the same thing, hoping the valve repair holds up. The guy that gave me the aluminum putty says he used it years ago on a 250cc dirt bike that ripped the threads out of the spark plug hole. He used this stuff to make new ones, and say he used it like that for a couple years, till he sold the bike.

Every day it runs, is more money in my pocket.

 

[handirifle]

Well, mowed for about 90 min today, and she still purrs like a kitten.:thumbsup:

Keepin my fingers crossed. That aluminum putty is amazing stuff.

 

[WilliamTO-35]

I'm glad you got your engine running. Products like JB Weld are epoxy with metal filings added, and an exhaust valve seat is a tough environment for epoxy. I hope it lasts. I had a valve seat fall out on a Techumseh engine, but I was able to do the peen and pound routine to reinstall it. I also had a valve stick open on another Techumseh engine. The valve stuck just after the guy next door borrowed the mower, and mowed with the throttle in the " choke" position . I think all of that fuel washed the oil off of the valve stem, and caused it to stick. My other neighbor gave me his riding mower with a 14 hp. Kohler engine that had thrown a connecting rod. He never checked the oil, so it was no surprise the rod went. I was able to find a brand new replacement short block on eBay for around $300, a lot less than the retail price of $800 or $900 . I had to find a different oil pan to fit the engine into my mower, but there again it was cheap on eBay. I was lucky on the output shaft specs. Kohler made several different shaft configurations, but my mower used the flywheel end to connect to the driveshaft, and the old flywheel works fine on the new short block. The mower is a heavy duty Deutz Allis hydro model, and well worth the effort to install another engine.

 

[handirifle]

I am amazed myself that this thing runs. I used it today for about 4 hrs straight, at or near full throttle. Still purrs on idle.

The dealer also told me of a repair for a stuck valve (which is what he first thought my problem was). He said to spray break free or similar onto the stem of the valve, and push on it. He claimed most of them will come loose again. Since that wasn't the problem, I never got to test that theory.

Glad you could peen yours, mine was beyond peening because it had hammered away too much material. I will look tomorrow, and post the name of the stuff I used. I ham a happy camper, so far.

 

[WilliamTO-35]

Besides overheating from blocked cooling fins, I think that running an engine at excessive rpm will lead to premature failure. While my Kohler is rated at 3600 rpm for 14 maximum horsepower, I mow at 2600 to 2700 engine rpm.
The engine has plenty of power at that speed, and if I get into very high grass or weeds, I slow down my forward speed or raise the mower deck to compensate. Mower deck drive belts also tend to burn up if overloaded .
I installed a small, digital tachometer/hour meter on my riding mower to keep track of rpm. I've long been amused at the difference between a Techumseh horsepower in a Sears mower and a Kohler horsepower. I had several Sears riding mowers with 12 hp. Techumseh engines and 38 inch mower decks, and they just barely had enough power to mow higher grass. My current mower has a 14 hp. Kohler and a 42 inch deck, and breezes through high grass without hesitation. There's a lot more than just 2 hp. difference between those engines ! I've also been happy with the smaller Briggs and Stratton engines I have on my 5500 watt generator, power washer, push mower, and snow blower. They usually start on the first pull, and run fine. The only problems I've had with recent vintage small B&S engines are the gas primer bulbs on some carburetors. Those bulbs seem to work sometimes, but not work other times. Fortunately, the generator and snowblower engines have a real choke, and not a primer bulb.

 

[handirifle]

I can imagine the engines were in all likely hood rated for the claimed HP, but what they do not tell is the torque. kinda like comparing gas engine hp to diesel hp. A 16hp diesel will do WAY more work than a 16hp gas engine, more than a 30hp gas engine, most likely. Your 14hp Kohler probably has a lot more torque.

As for me and running mine at high rpm, it was either that or the grass didnt get cut. This is a 20hp tractor, with 52" cutting deck, set up as high as it will go, BUT the grass is 12-18" tall, and a lot of it was wet. Most of the time I was never taking more than 1/2 the cutting width, and that's in 1st gear. I know this grass would tax most any riding mower. I'd much rather use a finish mower for my Massey Ferguson tractor, but my land is very soggy right now, and will be most of the summer, and I have gotten the tractor stuck twice already, and have no plans on taking it out there again, until it's drier.

I prefer to run it at about 1/2 to 3/4 throttle, but my grass was so tall, from the 20+ inches of rain we got on the last two months, and having the mower engine apart, I had no way to cut it. Besides, this was the first two dry days in a row we've had in almost two months.

If and when this dies, like I have said, I will replace it with a 26hp Husqvargna.

Cutting it from now on ought to be easier on me and the mower.

 

[handirifle]

Well, the saga continues.

As expected (not hoped) the previous patch did fail. big time. Back to square one with this project. I did get three mowings from it though, so not bad. These are 3hr mowings too.

I pulled it apart, again, and took another look. Yup it failed. So, this time I have taken a different approach. All this cause I'm broke/cheap and am trying the best I can to avoid spending three grand on a new mower.

This time, I used my handy little 7x12 lathe, and made a steel sleeve to hold the valve seat in. Not having access, or the funds, to pull the engine completely apart, and take it to a pro machine shop, I used (yes I really did) a 1 1/2" bi-metal hole saw to open the area around the previously partly destroyed section of block that contained the valve seat.

I am replacing the exhaust valve guide this time too, as it appears to be worn as well. Might have been part of the reason for the quick failure of the last patch, might not too.

So I machined a rod that fit the inside of the old valve guide, and would fit into the hole saw, and my 3/8 drill (did I mention this was a high dollar machine job?). I then drilled (using the term loosely) the valve seat area. This was scarry as all get out, cause now there was no turning back.

Once done, I measured the ID of the hole, and cut machined a section of
1 1/4" sched 80 steel tubing that I bought for this purpose. I machined the outside (1.5" roughly, don't remember exact size) to fit into the newly "machined" block. Then I machined the inside to allow me to press fit the old valve seat. Once done, I "pressed" the new setup into the block, and peened it into place. below are three pics of the work done. Sorry I didn't take pics as i went, my hands were too dirty to hold my phone.

I took a pic of the new sleeve with the valve seat, pressed in.

Then I took one with the exhaust valve partly inserted

Lastly is one with the valve completely seated. You can see the peening marks around it, to hopefully keep it all together. This thing fits tight in there, so I have high hopes.

My big concern, is this time, when I pulled the head off, there seemed to be a lot of oil in the cylinder, so I am hoping that the crap from the previous repair didn't take out an oil ring when it came off. We will see, I have about $50 into this repair this time. I am currently waiting on the new gaskets and valve guide. Supposedly tomorrow at noon, so in a day or so I will post the result of THIS patch job.

Anyone have any idea what the head bolts should be torqued to? I torqued them to about 50lbs last time, but was a guess.