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I have an old Snapper RER, model 33114S with a Briggs 12.5HP L head that burns about a quart of oil and hour and only has about 60PSI on a compression test. Oddly enough, it only has noticeable smoke on startup; after a valve job didn't change anything significantly, I've been looking into rebuilding the engine, but I just had a chance call from a friend who has an 18.5HP Intek Plus engine (PN:31p7770348e1) that he'll give me for the price of picking it up...about a 3 hour drive away.

He said it has about 10 hours but has a camshaft with a bad lobe, which seems somewhat common on those engines from some forums I've been reading.

Anyhow, since I dont have the engine here to compare to the current flat head engine, I was wondering if anyone here can tell me if this will easily work on this mower.

I've never had a decent over head valve engine for my mowers, so for just the work of installing a new camshaft, it sounds tempting to me but I dont know if the output shaft will work with the Snapper pulley or if I'll have trouble with the throttle cable, choke or anything else working with the mower.

I've tried to read about engine swaps on these, but haven't seen one using an 18.5 Intek for a swap on my particular mower.

Any thoughts on the matter would be welcome.

There should be no real problem.
The L head engines have a smaller mounting center than the OHV's so you might have to drill some new holes or file the old ones out and fit a heavy washer underneath.
The wiring might be different but there is nothing that can not be worked around.
Ony big problem I have had repowering old RER's is the ones with a deep dish the motor sits in the longer OHV engines foul so some stragic hammer, saw or file work might be necessary.

bertsmobile1 said:

... the ones with a deep dish the motor sits in the longer OHV engines foul so some stragic hammer, saw or file work might be necessary.

Click to expand...

I'm not fully sure I understand this part here. Can you dumb it down for me?

Opps I forgot my manners

:welcome:

The intek is longer from the crank shaft to the end of the head.
Some RER's have high walls surrounding the engine and the longer engine can foul on the wall
When you fit the new engine it is good idea to have the crank shafts in exactly the same position so belts will line up properly.
I have no idea what your Snapper looks like, we did not get Snappers down here and when we did they were rebranded with a local name.
We did get a lot of Murray RER's both as Murray and rebranded as Victa.
The body of these is sort of like a shallow bath tub and when I repower these I have to cut a slot in the back to clear the longer cylinder.
And please do not feel embarrased about asking questions

bertsmobile1 said:

Opps I forgot my manners

:welcome:

The intek is longer from the crank shaft to the end of the head.
Some RER's have high walls surrounding the engine and the longer engine can foul on the wall
When you fit the new engine it is good idea to have the crank shafts in exactly the same position so belts will line up properly.
I have no idea what your Snapper looks like, we did not get Snappers down here and when we did they were rebranded with a local name.
We did get a lot of Murray RER's both as Murray and rebranded as Victa.
The body of these is sort of like a shallow bath tub and when I repower these I have to cut a slot in the back to clear the longer cylinder.
And please do not feel embarrased about asking questions

Click to expand...

I think he said that the engine might hit the fender.

You may need to trim off some or all of the flared part.

Well, thanks for the information from you guys! It sounds suspiciously like I need to try it to make sure it'll work and maybe report back later.

After getting texted a few measurements, it LOOKS like the bolt pattern is pretty close to the flat head I have and the output shaft diameter is pretty close...at least as far as I can tell from measuring what's on my mower and looking at the pictures my pal sent me with a tape measure for comparison.

Either way, I think I'll be going through the effort of picking up and repairing the engine just to try it on the mower.

Worst comes to worst, I spend a few bucks on a cam, have an engine I can sell and rebuild the flathead I currently have; it should last years after I have the cylinder bored and honed and replace valve seats and guides.

The shaft will be the same diameter and length it is fairly well standard on vertical engines.
7/8" push mowers
1" domestic ride ons
1& 1/8" commercial ride ons.

Sneaky sizes
20mm rest of the world push mowers
25mm rest of the world ride on mowers
30mm rest of the world commercial mowers.

AFAIK Inteks only metric size is 25mm so check your pulley will fit before you start spending money.
The mounting holes go out about 1/2".
make up a cardboard template of your existing holes and one for the new engine to work out where you will have to cut
Small engine supliers and small engine warehouse both have links to engine drawings so you can go there and look up the exact placement of the bolt holes.

Maybe this thread will help someone down the line, so I'll try to keep it updated.

The latest is that I haven't forgotten that I said I would let you guys know how it goes.

This is the newest (yet not very useful) update:

I picked up the engine. It had the sump pulled and the old camshaft was still there; the exhaust lobe was perfectly round, as if it had been machined that way.

The new cam is installed and the sump is back on but the muffler went somewhere else, so I'm waiting for one to be shipped to the mower shop a few miles away from me. Everything LOOKS like it'll match up to the existing mounting holes and what not on my mower, but I'm not pulling the old engine 'till I have all of the parts to swap the engine out in a few hours. I still have to maintain my property, so I won't pull the ailing engine 'till the new one is fully up and running.

The piston was already at TDC, so I was able to look up inside of the cylinder from the bottom and I saw good crosshatch and no obvious wear, so the story of this engine just having a few hours on it seems to hold up.

It looks like I'm a valve adjustment, oil filter and install away from having a new over head valve engine on my old mower!

Not a bad situation to be in, really, as far as lawn tools goes.

Another update:

I picked up and assembled the over head valve engine. I thought I'd have to wait a while longer to install it as some hardware was missing that I couldn't find in town. It showed up today, so I went to work removing the old engine. After getting the drive pulley off, it fits the new engine output shaft just fine, so I'm sure this is going to work out great.

While I haven't done the full swap yet, the mounting ears of the new engine and old measure out OK with a tape measure but the old (I don't know if this is stock or not) mounts with nuts and bolts and the new has threaded bosses that are a different size from the old mounting hardware.

Just eyeballing things, it looks like the throttle will hook up just fine but I may have to change some of the electrical connectors as I don't have any plugs on my mower that fit up to the new engine. I've found a wire diagram so it shouldn't be a big deal.

Aside from heat and humidity fighting me, this should be a simple engine swap.

Next time I update this thread, I'll update the tags and make it easier for anyone later on down the line who is doing an L-head to OHV engine swap to find information.

Ok, so I got the engine installed and it went pretty great. The only problems I had was the exhaust wanting hit on one of the rails on the back of the mower and I had to flip the fuel tank in it's little mounting bracket, but I've adjusted the drive disk and installed the throttle and everything looks like it'll work fine. There's even enough room to install and remove the oil filter easily!

Next step is to wire it up, which I'll do later and should be back in business quickly.

i know this an old thread maybe some folks still around

I'm in a similar swap and cant seem to get the motor/exhaust correct.

anyone have a pic with the muffler on and out of the way.

I cobled the muffler from my smaller engine and the new setup is a bit too loud

id like to try to put the muffler for the 17 HP on but cant figure out the pipes


thanks

Please refrain from posting the same question in multiple places as it gets very confusing.
The bad news is mufflers are mostly made for the mower manufacturer so are specific to that engine in that mower.
Thus the "correct " muffler for a mower can run to $ 150 while the standard one is only $ 40
Your set up looks quite well done but yes the pepper pot muffler would make it a touch on the noisy side.
There is a deflector plate # 393761 or 790538 that should fit over the top & screw in with some self tappers
You could simply try that with it pointed directly backwards away from your ears.
The biggest muffler that I think you could fit is # 394170 which went on the 15 Hp inteks .