Craftsman lawnmower B&S engine replacement.

rutbuster1

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I would take the engine off the deck and open it up. It's most likely the rod seized to the crank. Get a replacement rod and clean the aluminum off the crank with acid and polish it back to new. It can probably be repaired for $50.
That's exactly what I'd do first. Most likely it's the rod. Unless it put a hole in the crankcase. But heck, if it's not to bad, that can be patched up. I've done it before. lol
 

fzullo

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I hope I am posting this in the right place, My Grandson ran his Craftsman mower dry of oil, and it locked up. I want to replace the engine I need help finding the right engine and any other advice that you guys can provide. Model 247.378330 B&S platinum 7.25 163cc
https://www.smallenginewarehouse.com/ always had luck with them.
 

TobyU

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I hope I am posting this in the right place, My Grandson ran his Craftsman mower dry of oil, and it locked up. I want to replace the engine I need help finding the right engine and any other advice that you guys can provide. Model 247.378330 B&S platinum 7.25 163cc
It is NEVER cost-effective to have a new engine put on a mower especially a push mower..
It is not very cost effective to buy a new one yourself and put it on.
The ONLY wait it's cost-effective is if you can buy a good used engine and transplant it.
It is also hardly ever cost effective to disassemble the engine and try to fix it internally as a replacement engine of the used variety is a far better cheaper option.

Having said this, it may not be shot..
I get a handful of them in every year locked up due to lack of oil and I'm able to save 85 to 90% of them.

If it's just locked up and hard to pull and it didn't snap the rod so there's no compression at all, don't try to pull it anymore and stop right there!

Pull the spark plug out and pop the handle bolts out or whatever to allow it to fold so you can stand it on its back wheels with the spark plug hole straight up in the air.
Get you some PB blaster and spray an get into the hole until you fill up the cylinder about an inch full of PB blaster.
Then, get you some Lucas chain lube, it is far better than any other chain lube I have ever used so buy this. And the next day after sitting like this spray an inch of that into the cylinder.

Let this sit overnight too.
Now get you a quart of 5W-30 fully synthetic oil but this is a little forgiving as you can use 10W30 or 0w30 or 5W20 as long as it's full synthetic and pour the whole bottle into the crankcase.
Yes, you're overfilling it by a lot but you want to.
Now once you filled it up over full, you need to stand it on all four sides.
You only need to do this for a few minutes and actually a minute or two will suffice on each side.
Stand it up on its back wheels for a minute or so then stand it on its front wheels for a minute or so. Watch out because the oil and stuff that you sprayed in there might run out.
Then flip it on its right side for 90 seconds and then on his left side for 90 seconds.
Then do the same procedure again.
Fix the handles back and shove It Forward and back really hard 8 or 10 times to slosh the oil everywhere inside.
Now spray your PB blaster and Lucas chain lube back into the cylinder one more time getting about a half inch of coating or whatever and then flip it up on its back wheels but you may already have it there, and grab the blade while looking at it from the bottom and turn it clockwise but only one inch!
1 in only. Then go back a half an inch.
Then go an inch forward and then back a half an inch.
Then go 3 in clockwise and back 2 in.
Then go for and back three. Do this 10 or 12 times and you'll probably feel it start to loosen up.
Then go a complete slow turn or two clockwise again and then sit the mower back down and all four wheels.
Make sure your engine zone control cable is pulling when you squeeze the handle or this could have been the problem altogether but I'm kind of doubting it and then pull the rope a few times.
All this is done with the spark plug out.
This will blow some more crap out of the spark plug so wipe that off of the rag and it should get easy to pull pretty soon.
Now let the plug back in and the spark plug wire on and try to start it.
You might have to take the air filter out because it might have gotten oil or gas on it but you can run it without the air filter for test purposes.
You might need a little bit of carb cleaner spray in the hole of the carburetor to get it to run but nine times out of 10 they will fire up and run.
Now the tricky part is do they knock and rattle or sling a rod in 15 seconds which is uncommon, or do they have a little bit of rattle when they first start and a little bit of rattle when you let go of the handle and they Coast down to a stop and the big question is how much do they smoke?
I have done so many this way that had you have not known they were locked up you would never suspect a problem and they run for years.
I have had others that have a little bit of rattle noise on spin up and spin down when they start and stop.

I have to have some that smoke a little bit and you can still deal with that bye a better oil.
And some smoke like a freight train and some run for about 15 seconds and the rod comes loose so it's a done deal
I save over 90% of them and they're good useful mowers afterwards.

Now note that you have it over full with oil and you only want to run it for 10 or 15 seconds..
Now you need to change that oil and drain it out
You'll get tons of nasty gray metal particles out with it.
You might want to get another quart of synthetic 10w30 and run it for about 20 or 30 minutes or at least one mow and change it again.
That will help pull all the dirt out of it and the metal shavings and lubricate it well but I would not recommend using synthetic in the future.
It will he can smoke too much with it.
Go buy some straight 40 weight diesel oil or even better Valvoline VR1 racing oil SAE 30 or SAE 40 which is even thicker.
Fill it slightly above the full Mark but not over an eighth of an inch above the full mark and keep an eye on the oil regularly.
This works far more than it doesn't.
 

TobyU

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That's exactly what I'd do first. Most likely it's the rod. Unless it put a hole in the crankcase. But heck, if it's not to bad, that can be patched up. I've done it before. lol
Possibly but I think it would cost more than that just to get the rod and the gasket and the quart of oil.
It might be better but I never find it's the most cost-effective way to repair an engine problem that's internal crankcase.
People throw away so many mowers or you can buy one for 25 bucks or less that won't start simply because the carb is gummed up..
Find one with the same engine and they can just swap the carburetor over when they swap the engine and be back in business.
It's cheaper to do it this way than it is to buy the parts and it's faster.
Then, you have a mower that could be decent looking where you can put the other engine back on it and sell that mower say needs engine or won't start or whatever and get most of your money back.
It's really the most ideal situation.
 

rhkraft

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I agree with 'J', A new mower is probably less than a new engine. I've done this before with a 5 hp string mower. The replacement engine was $310. A new mower was $289. Unless you want a project for your grandson?
 

Cfs

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I would try putting a mix of 50/50 ATF and acetone in to the spark plug hole. Let it set in the engine for a few hours … you can also remove the muffler to get access to the exhaust side and add some of the ATF mix there too. After it sits a few hours try moving the blade a little to the left then a little to the right back and forth and see if it will break loose. If the damage was not so great as to weld the rings into the piston groove (rings can still flex in and out) you may be okay. Chances are you have damage to the piston and you will need to disassemble the engine and replace the piston and rings… if that is something you want to try
Spit
 

rutbuster1

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Possibly but I think it would cost more than that just to get the rod and the gasket and the quart of oil.
It might be better but I never find it's the most cost-effective way to repair an engine problem that's internal crankcase.
People throw away so many mowers or you can buy one for 25 bucks or less that won't start simply because the carb is gummed up..
Find one with the same engine and they can just swap the carburetor over when they swap the engine and be back in business.
It's cheaper to do it this way than it is to buy the parts and it's faster.
Then, you have a mower that could be decent looking where you can put the other engine back on it and sell that mower say needs engine or won't start or whatever and get most of your money back.
It's really the most ideal situation.
I got my last push mower for $20 seven years ago. Like you said, a simple fix. All that was wrong with it was too much water in the fuel. I cleaned the carb anyway though. It's still running good though. I'm on the hunt for me another fixer upper now.
 

TobyU

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The cheapest I have ever seen a new vertical push mower engine like this was either 169 or 179 at a Rural King local store several years ago.
Back then, before mower prices had skyrocketed and gone up $100 or more, it was not cost-effective at all to even consider replacing one of these.
Now it might be a little bit better but still.....
It is never going to be cost-effective to put a 200 plus dollar engine on a push mower when you have the other option of just going and buying a good running used engine or a used mower for parts etc or maybe one that even runs great and a wheel has broken off or the transmission no longer drives the mower.
People dump these things for 50 bucks and far less.
The only thing you have to be careful about is the crankshaft come in two common sizes of diameter.
You can still make the other ones work if it's not the same size but it's a lot more complicated and sometimes you have to buy or source a new blade adapter to get it to fit and also to get the blade and the proper position up inside the deck not being too far down or too far up.
Most the time you get lucky though and the shafts are the same size so you just take your old stuff off and put it back on the replacement engine, three bolts and you're done.
 
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