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Hi
I have a Murry with a 17.5 B&S Twin motor that runs awesome but it leaks on the left side of the bottom pan. I cleaned it very good and there is no doubt that's where it's leaking from when running. My question is, is it common? I've looked for hours with no luck. I don't think it's just blow by as it runs to good.

Thanks for any help with this.

I've never seen an opposed twin leak at the sump gasket, but that doesn't mean it can't happen. Every engine gasket can go bad and start leaking.

Thanks for the reply, Yea I find it odd also. I cleaned it very good and got down with a light with it running and you can watch it run out of the pan. It's an old motor I believe it's from the 90s but it runs great.

My next question is, is it a big deal to replace the gasket? Working on a motor is no problem for me but I've never replaced one on a small motor.

The hardest part is getting the engine pulley off to get the engine out of the mower.
Expect to break an exhaust bolt .
The only trick is setting end float which is done by varying the number of gaskets .

I've got a Full service manual for the Twin i can upload/PM you some pages if you need.

bertsmobile1 said:

The hardest part is getting the engine pulley off to get the engine out of the mower.
Expect to break an exhaust bolt .
The only trick is setting end float which is done by varying the number of gaskets .

Click to expand...

The end float? So you need to figure how thick of a gasket you might need?

I might be wrong, I've been wrong before, but it looks like you can pull the motor intact and turn it upside down take off the pullys and pan and change the gasket. LOL I guess I'm looking at it like a small block chevy motor? Is it not that easy?

Scrubcadet10 said:

I've got a Full service manual for the Twin i can upload/PM you some pages if you need.

Click to expand...

I will let you know and thanks for offering to help. I want to see if it's worth the trouble. I sure don't want to part it out as it's just to good of a mower.

troy-built said:

The end float? So you need to figure how thick of a gasket you might need?

I might be wrong, I've been wrong before, but it looks like you can pull the motor intact and turn it upside down take off the pullys and pan and change the gasket. LOL I guess I'm looking at it like a small block chevy motor? Is it not that easy?

Click to expand...

That's how i did mine. I would also change the crankshaft seal, cheap insurance.

if it's still working good and running good, it's definitely worth the effort.

the sump gaskets for this motor come in .005" thick, .009" and .015" thick.

Oil seal part, Briggs and Stratton 291675S

Scrubcadet10 said:

if it's still working good and running good, it's definitely worth the effort.

Briggs and Stratton 42A707-2238-E1 Parts Diagram for Sump

Briggs and Stratton 42A707-2238-E1 Sump Exploded View parts lookup by model. Complete exploded views of all the major manufacturers. It is EASY and FREE

www.jackssmallengines.com

the sump gaskets for this motor come in .005" thick, .009" and .015" thick.

Oil seal part, Briggs and Stratton 291675S

Click to expand...

Thank you, That is very helpful.

Scrubcadet10 said:

That's how i did mine. I would also change the crankshaft seal, cheap insurance.

Click to expand...

Oh yea I wouldn't go that deep and not change that seal but thanks for the suggestion.

Scrubcadet10 said:

if it's still working good and running good, it's definitely worth the effort.

Click to expand...

Yes it runs awesome. That's the only reason I'm even thinking about repairing it.

Scrubcadet10 said:

I've got a Full service manual for the Twin i can upload/PM you some pages if you need.

Click to expand...

Good morning. Could you send me the pages that cover how they recommend changing the gasket? Also is it better to take off the pulleys before or after you pull the motor?

Many thanks for your help with this.

bertsmobile1 said:

The hardest part is getting the engine pulley off to get the engine out of the mower.

Click to expand...

Sorry I just noticed this. So you have to remove the pulley before you pull the motor?

Varies mower to mowe but most only have a 2" hole for the PTO shaft and 4" to 6" pulleys
Flywheel can stay on but pulleys usually have to come off.
In any case they have to come off in order to get the sump off but it is a lot easier to remove if not in the mower

bertsmobile1 said:

Varies mower to mowe but most only have a 2" hole for the PTO shaft and 4" to 6" pulleys
Flywheel can stay on but pulleys usually have to come off.
In any case they have to come off in order to get the sump off but it is a lot easier to remove if not in the mower

Click to expand...

Got ya. Are the threads on the mower right hand or left hand?

Many thanks

I've been doing some reading and I found this interesting.

Although the original gasket had a weak spot wear it blows out. If you use some silicone when you put the new gasket on, its unlikely it will ever fail again. But if you just replace it, you should get 15 years out of it. Once the engine is off the chassis, it is very easy to replace the gasket. Opposed twin Briggs are great tractor engines and that gasket is the biggest known thing to go bad, otherwise these are very reliable engines.

troy-built said:

Got ya. Are the threads on the mower right hand or left hand?

Many thanks

Click to expand...

On mine it was righty tighty, lefty loosey.

Scrubcadet10 said:

On mine it was righty tighty, lefty loosey.

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That's what I thought but I learned a long time a go on a motor of any kind it's better to ask just to be sure. Thanks

Oh by the way could you get me the pages out of your manual that's tells how they suggest to set up the float on the pan gasket?

Here's all the manual says for the end float, (play)
Crankshaft end play is .002"-.026" on vertical crankshaft engines with a .015" gasket in place. If end play is less than .002" additional gaskets .005" , .009" may be added to obtain correct end play.
if end play is more than .026" with a .015" gasket in place, install thrust washer (PN 222951). install thrust washer on PTO end of crankshaft, install on the magneto side of crankshaft if there is a ball bearing in the PTO side only. then adjust end play as described in the previous paragraph ^^.

This video maybe more helpful than those few paragraphs.

Ok now I understand what you were talking about float/end play. Thanks for the video that was very helpful.

Thanks

Usually on the twins, you don't have to remove the exhaust pipes, they usually set down into the muffler mounted on the tractor.

Fish said:

Usually on the twins, you don't have to remove the exhaust pipes, they usually set down into the muffler mounted on the tractor.

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Yea that's what is looks like to me also.

Well that was the easiest motor I have ever pulled. Nothing broke and it came right apart. Nothing was rusted or stuck. 45 min and it was on the work bench. Another 15 min and it was a part and I just ordered the gaskets and seals.

It should be back together next week.

Thanks again for the help.

Oh by the way you could tell the gasket was leaking it had oil on both sides of it in several places.

Fish said:

Usually on the twins, you don't have to remove the exhaust pipes, they usually set down into the muffler mounted on the tractor.

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Not on this one the muffler was bolted to the motor, once the bolts were removed it slid right off very easily. It's a great design.

Update, My gaskets came in I put it all back together and it's running like new now with no leaks. Thanks for all the help.

Now to put on a new set of shoes as these are dry rotted BAD. Just ordered all 4.

glad to hear it!

OIl is cheap. Wally's mart has a gallon of 30w for like $9.75. Is it pouring out or just making a small mess?

Hey nice fix. Glad to hear she is back up slinging grass.

slomo

Yea, I was amazed at how simple it really was. But I'm sure it not being rusted at all helped a lot.

Thanks again

slomo said:

OIl is cheap. Wally's mart has a gallon of 30w for like $9.75. Is it pouring out or just making a small mess?
Hey nice fix. Glad to hear she is back up slinging grass.

slomo

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Yea oil is cheap but a gallon wouldn't have lasted long as bad as it was leaking. But it would have killed the grass so I wouldn't have had to cut it as much and as often. LOL

Oh yea it was very bad you could see where the gasket had blown out once I got it apart. Plus it only cost $25.00 to fix it. That was two gaskets and a seal.

I'm not using it to cut grass anymore as I have a zero turn now for that. I'm just going to use this one to aerate my lawn, pull trailers and such things as that. This one takes to long to cut grass. 5 hours longer. LOL

Similar situation on my twin Briggs 26 horse. Must be of different design as it is widely known to leak.
Bought a gasket and cam and will get to it eventually. For now, I slowed it down by 95% by pulling one bolt at a time and coated with black RTV. Then torqued. Next bolt and next until completed.

Doc8404 said:

Similar situation on my twin Briggs 26 horse. Must be of different design as it is widely known to leak.
Bought a gasket and cam and will get to it eventually. For now, I slowed it down by 95% by pulling one bolt at a time and coated with black RTV. Then torqued. Next bolt and next until completed.

Click to expand...

Man don't waste time doing that. Just pull the motor flip it upside down and take it apart it's very easy.