B&S compatibility (parts swapping)

turbofiat124

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Just a heads up on something. I'm sure I'll figure it out once I get into it.

I bought a Snapper riding mower used (~2 years old when I got it) which I've since sold. I believe it was built in 2000 or 2001. The engine made it through the summer until fall before it threw a rod through the block. Just a guess but the engine failed just a little after 2 years, maybe less than 200 hours based on the size of the guy's yard. Just after the 2 year warranty had expired!

I saved the engine for parts "just in case". The engine was full of oil and not making a noise or knock prior. I was mowing and the engine just stopped running. No loud bang. It looked to me as if the nuts on the end of the connecting rod just worked loose. I found a connecting rod nut in the crankcase.

So I got this Murray riding mower (2005) through a Craigslist trade.

I apologize for not posting the model number off the 15.5 HP engine (valve cover is a bit rusty) but just from looking at these two engines, I'm curious if the exterior parts are compatible between these engines. The 2000 model is a 14 hp and the 2005 engine is a 15.5 hp.

I want to use the following parts:

1) carburetor
2) recoil starter.
3) electric starter motor (yeah, I know redundant)
4) Can I use the cylinder head if I ever needed to?

The engine covers are different but these engines look pretty much the same otherwise. If I want to use the recoil starter, what parts do I need to swap? Just the cover or do I need to swap flywheels? I'm know if I use the 14.4 cover , I'll need to use the air cleaner housing since the air cleaner is built into the plastic over used on the 15.5 model.

Thanks!
 

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bertsmobile1

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:welcome::welcome:

YEs, no, perhaps, maybe.
Carbs, alternators, flywheels ( should be considered part of the alternator ) should all interchange.
Heads will depend upon the series of the engine.
Briggs engines are in series or families with the same capacity.
Small Hp differences are done with carbs , big differences are done with bore & stroke.
The easiest way to see if the heads SHOULD interchange is to check the part number of the head gaskets for each engine.
If it is the same the heads should interchange.

On most B & S engines the crankshaft on pull starts is longer than the crankshaft for electric start only engines as the pull starters usually work on the 4 ball clutches that mount onto the protruding end of the crank above the flywheel.
 

Tinkerer200

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Note that the crankshafts of newer engines were drilled and tapped to take a screwed in extension to accommodate a recoil starter.

Walt Conner
 

bertsmobile1

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Thanks Walt
Not come across one of them yet
 

turbofiat124

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Lots of them this side, that way just make one crankshaft to do both.

Walt Conner

You are correct!

I removed everything from the stuffed engine I needed only to remember that all three of these B&S engines without recoil starters on my riding mowers (15.5, 17.5 and 21.1) all have bolts holding the flywheel to the crankshaft where the 14 B&S uses the starter clutch as the "bolt" to hold the flywheel to the crankshaft which has a male threaded end.

I have not removed the flywheel from the 15.5 (the one I am wanting to install the recoil starter on) but it kind of appears that the flywheels between these two engines are the same.

I was telling that guy I work with who works on lawnmowers what I discovered and he said someone made a kit to install recoil starters on engines that uses a bolt. Looks to me like all I would need is a union that would thread into the crank on one end and onto the starter clutch on the other end would do the job. I don't know if this is the kit he is talking about. He said he was going to send me a link.

I did find this item listed below I think is the conversion kit he is talking about. But there are cheaper ones on Ebay.

https://www.ebay.com/itm/New-OEM-Br...056125&hash=item261d50e661:g:CqEAAOSwx9Rc5JIr

Note the zinc plated part. I don't recognize this part on either engine.

On both flywheels there are two bolts. The bolts on the engine from the recoil engine secure some sort of ring that goes under the starter clutch. On the engine without the recoil, these bolts are just there and seem to serve no other purpose.
 

Tinkerer200

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"On both flywheels there are two bolts. The bolts on the engine from the recoil engine secure some sort of ring that goes under the starter clutch. On the engine without the recoil, these bolts are just there and seem to serve no other purpose."

These holes serve two purposes, hold adapter for flywheel screen in some instances and are used for the B&S flywheel puller. The adapter for recoil starter is a standard B&S part for drilled tapped crankshafts. That illustration you sent is some sort of after market I guess for crankshafts which are not drilled.

Walt Conner
 

turbofiat124

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"On both flywheels there are two bolts. The bolts on the engine from the recoil engine secure some sort of ring that goes under the starter clutch. On the engine without the recoil, these bolts are just there and seem to serve no other purpose."

These holes serve two purposes, hold adapter for flywheel screen in some instances and are used for the B&S flywheel puller. The adapter for recoil starter is a standard B&S part for drilled tapped crankshafts. That illustration you sent is some sort of after market I guess for crankshafts which are not drilled.

Walt Conner

After posting this I went to take another look at this engine and the threaded piece I am talking about already exists! See enclosed photos.

I don't know why I didn't notice this to begin with.

I just got to pull the flywheel on the recipient engine to see if it matched the end of the crankshaft and check to see if there is a difference in flywheels.

One other thing which is trivial because I think I know a way to get around this. They made a lot of changes between these engines. The oil dipstick bracket, air cleaner assembly, intake manifold (slightly) for example.

The PVC valve (if that's what it's called) is mounted on top of the 15.5 engine where it's mounted on the side of the 14 engine. The elbows that holds the air cleaner onto the carb are different. On the 14 engine, the hose goes into the bottom of the cleaner. where it goes into the side of the 15.5 engine.

My idea was to cut the hose and use a piece of tubing so I can lengthen and angle the hose to where it needs to be. I don't think I'll have to swap intake manifolds. The 14 uses a screw to support the air cleaner but I don't think it's really necessary.

EDIT:

So today I decided to see if these parts would interchange and so far so good but the more I get into it , the more heat shields have to come off and swapped from the doner engine.

I didn't swap flywheels but looks like it might has to have to come off in order to get to a small bolt holding a heat shield on the carburetor side which is interfering with the metal cover. I'm going to see if I can get to it with a 1/4" wrench so I don't have to remove all this stuff AGAIN just to get the flywheel off. Also there is a hugh heat shield around the muffler and a shield behind it that may have to come off.

The dipsticks do not seem to interchange (hole in the block is bigger) but the one from the 15.5 looks like it's going to overlap the metal cover.

So in other words when B&S went to this plastic cover and deleted the recoil starter, they changed everything.

It's not a big job, just allot of stuff to take off, fasteners to keep track of and swap over.
 

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Tinkerer200

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After posting this I went to take another look at this engine and the threaded piece I am talking about already exists! See enclosed photos.

I don't know why I didn't notice this to begin with.

I just got to pull the flywheel on the recipient engine to see if it matched the end of the crankshaft and check to see if there is a difference in flywheels.

One other thing which is trivial because I think I know a way to get around this. They made a lot of changes between these engines. The oil dipstick bracket, air cleaner assembly, intake manifold (slightly) for example.

The PVC valve (if that's what it's called) is mounted on top of the 15.5 engine where it's mounted on the side of the 14 engine. The elbows that holds the air cleaner onto the carb are different. On the 14 engine, the hose goes into the bottom of the cleaner. where it goes into the side of the 15.5 engine.

My idea was to cut the hose and use a piece of tubing so I can lengthen and angle the hose to where it needs to be. I don't think I'll have to swap intake manifolds. The 14 uses a screw to support the air cleaner but I don't think it's really necessary.

EDIT:

So today I decided to see if these parts would interchange and so far so good but the more I get into it , the more heat shields have to come off and swapped from the doner engine.

I didn't swap flywheels but looks like it might has to have to come off in order to get to a small bolt holding a heat shield on the carburetor side which is interfering with the metal cover. I'm going to see if I can get to it with a 1/4" wrench so I don't have to remove all this stuff AGAIN just to get the flywheel off. Also there is a hugh heat shield around the muffler and a shield behind it that may have to come off.

The dipsticks do not seem to interchange (hole in the block is bigger) but the one from the 15.5 looks like it's going to overlap the metal cover.

So in other words when B&S went to this plastic cover and deleted the recoil starter, they changed everything.

It's not a big job, just allot of stuff to take off, fasteners to keep track of and swap over.

Well you should post model numbers when asking engine questions. For one thing there is overlap between 28 series and 31 series engines with respect to the sticker HP. HP does not identify the engine. Also, sounds to me like you have an original style 28 series engine and a newer style 31 series engine. While many parts interchange between original style 28 series and original style 31 series, not so between original style 31 and newer style 31 even. Flywheel, crankshaft, sump counterweights are a few.

Walt Conner
 
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turbofiat124

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Well you should post model numbers when asking engine questions. For one thing there is overlap between 28 series and 31 series engines with respect to the sticker HP. HP does not identify the engine. Also, sounds to me like you have an original style 28 series engine and a newer style 31 series engine. While many parts interchange between original style 28 series and original style 31 series, not so between original style 31 and newer style 31 even. Flywheel, crankshaft, sump counterweights are a few.

Walt Conner

I found the model number on the 14HP but it's nowhere to be found on the 15HP engine. I thought B&S stamped the model numbers on the valve covers like my 21HP engine on my Husqvarna but both of these older engines there is not stamping.

I had to put this project on the back burner for awhile due to other things but I started working some more on it today.

Anyway here is what it comes down to. Remove basically EVERYTHING. The heat shields are different and are not compatible with covers. See photos of the cylinder shield. There is a notch cut out on 15HP shield but not the 14HP shield so it wont fit. But I did manage to trim some off the 15HP shield so it clears the 14HP cover.

Dipsticks tubes are different (hole is bigger in one block than the other). PVC valve (or whatever Briggs calls it) is on the top of one engine and on the side of the other.

It looks like after all is said and done, this will work but it's going to take a lot of hacking on the heat shields and the cover to clear the dipstick tube.

Also this mower must have spent some of it's life outside in the weather. Some of the bolts are seized. I broke one of the coil screws but was about to heat it up with a propane torch and remove it.

Not necessary but I am swapping coils and the starter. The starter hangs up and looks like a squirrel chewed through the plug wire. Since the other parts were good I thought I'd use them.

I can't say this was a worthwhile conversion considering how much stuff B&S changed on these engines in just 5 years. If I had to do it all over again, I would have bought the $65 conversion kit they sell. But I had this donor engine so it's not like I am having to spend any money. But my time is valuable. I've spent more time on this thing that I wanted to.
 

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