Exploring engine transplant - B&S 6.75hp / 190cc

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A couple of days ago, a killed my 10 year old B&S by accidentally running over a stump. At first, I thought the only damage was a bent blade. I restarted it, it ran for a minute or so, before it stalled and it won't start again. I know I probably shouldn't have tried to restart it, but it's done.

I may be able to get my hands on the same engine, though used, at what looks like quite a good price. Problem is, this version of the engine is on a pressure washer (the pump of the washer is damaged, and I really have no interest in the pressure washer side of it anyway).

I understand different implementations of these engines means they may be equipped differently. What sort of issues, if any, would I see transplanting this engine onto my mower?

Hoping for as close to plug and play as possible, or at the worst, some easily obtainable and easily changeable parts to make it work.
 
The biggest difference will be your blade driver/adapter. Different versions of the engines had different types of crankshafts to fit the OEM application, so the crankshaft snout diameter and shape (threaded, keyed, etc) is likely different. Additionally, if your mower is self-propelled, you'd have to make sure that the pulley will fit. A pressure washer engine will have a heavy steel flywheel instead of the light aluminum flywheel that the mower engine has...but this will be of no real consequence to you. It would be if you were going the other way, trying to put a mower engine on a pressure washer.

Honestly, the best bet, if this engine doesn't work out, is to find any mower engine complete with blade adapter and use that. It really doesn't matter the brand of engine. Mower engine bolt patterns are essentially universal, and flywheel brake cable connections are generally compatible as well. I've used a Honda engine on a Lawn-Boy deck where a Tecumseh engine once was. The flywheel brake cable worked just fine and it bolted to the deck just fine. Just this year, I went back to a different-year Tecumseh engine from a Craftsman mower...again, the Lawn-Boy's flywheel brake cable connects just fine and the Honda is on the shelf in the shed for another project.

I'd recommend finding a mower used with a rusted deck and a good engine. All you'd need to do then, for the most part, is freshen or replace the blade.

And if your current engine still ran after it hit the stump, even for a short while, it may not necessarily be a lost cause. You can pull the flywheel and check to see if the shear key has been damaged. If that was damaged, and the stress of running it one last time finally sheared it, the ignition timing would be off and it wouldn't run. So I wouldn't necessarily say that your engine is damaged beyond repair yet. If it ran without severe vibrations (which would indicate a bent crankshaft), it may still be good. Pull the spark plug and look underneath while someone pulls the starter cord and see if the crankshaft snout wobbles back and forth as it spins. If not, you may still have a usable motor there.
 
Thanks. I may focus on other lawnmowers as potential donors then, though a small engine shop figures, without looking at it yet, they can get it going for $100. I can probably pull it apart to look at the flywheel and shear key, but honestly, I am so insanely busy with other stuff right now, I'd rather just pay that $100.

Though if I can find an alternative less than that, and it is basically plug and play, I am willing to do that (or even better, a ready to go used mower in good condition). Of course, all so long as it's cheaper than the repair, otherwise, I'd rather have my B&S engine up and running again.
 
First (and most important) is the crankshaft has to be identical length. Most mower crankshafts are 3.156 inches long (3 5/32) Most pressure washers and mowers are 7/8 diameter, although some mowers are 25MM diameter(which is .98 inches, almost an inch) So if the length of the shafts are the same, you are getting close.

Next, pressure washers have a heavy flywheel. It will work fine on a mower, but would be better off swapping your lightweight aluminum flywheel. While the flywheel is off, you can swap the blade brake/kill switch components. Or you can use a kill switch.

Next, the carburetor on a pressure washer is adjustable to 3600 RPM for max power on a pressure washer. That is too fast (and dangerous) for a mower. Assuming the mowers are the same engine family, you can swap over your mower carb to the pressure washer engine so that your new engine runs at the same RPM for a mower. The primer bulb or auto choke are fairly easy to swap over too.

Basically, the swap can be done if you know what you are doing in about 30-45 minutes. For a novice/beginner, it could be a little too much...

Also, don't forget to re torque the head bolts. The head bolts on flat head Briggs engines are notorious for working there way loose on pressure washers.
 
Yes it would be much easier to find a good used mower engine, or if so inclined, check eBay for new engines. There is a good selection of new engines there for $99 to $150 usually.
 
I'm with hokiefyd on this:

it's not deemed "unserviceable" until you get things checked first:

Usually, when you hit a stump or similar, your flywheel key would have shifted or even sheared. Get that checked and replaced first (only 50c pc) and see if that works.

Q.
 
around here the "check it" price would be about the same as a 79$ chonda lawnmower engine.

so its not really feasible to get it "checked out" unless its the -free checkout, the buddy 12pack hookup, or <25$.
 
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Two part reply: First, is it really dead? Hitting a stump *usually* just results in the flywheel key shearing off. That will eventually prevent it from running since the magneto won't be generating voltage at the instant the points open. So check the flywheel, re-key it, and see if it runs smoothly.

If it's really locked up or vibrates like crazy even with a new blade and you have to replace the engine: There are 4 variables among versions of that engine, all related to the shaft.

1) Shaft diameter
2) shaft length
3) Thread
4) "heavy" or "light" flywheel.

Never use a "heavy" flywheel engine on a mower, as that greatly increases the damage when you do hit a stump. My bet is that a pressure washer engine will be heavy flywheel. You could probably swap on your light flywheel and go, if the other parameters match.

Following that, matching the shaft diameter and length is most critical so your blade adapter will fit, and so that the blade will be at the correct height inside the shroud of the mower deck. You can buy a new Grade 8 bolt in the thread pitch the new engine uses.

You can pick up common versions of the 190cc Briggs for prices that are only 20% or more than the junk engines at Harbor Freight.

Check this site:
http://www.equipatron.com/small-engines/...ft-engines.html
 
Originally Posted By: 440Magnum


You can pick up common versions of the 190cc Briggs for prices that are only 20% or more than the junk engines at Harbor Freight.



that are only Double or more than the Chinese honda clones at Harbor Freight.


-Fixed that for you.
grin2.gif


If I was spending 160$ to 200$ for an engine I'd go craigslist diving first. The HF 173cc honda clone if it fits your application can be had for 79$ frequently... Alternatively a whole new craftman mower with a briggs 190cc starts at 229$.. that's without any kind of deal.
 
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Originally Posted By: Rand
Originally Posted By: 440Magnum


You can pick up common versions of the 190cc Briggs for prices that are only 20% or more than the junk engines at Harbor Freight.



that are only Double or more than the Chinese honda clones at Harbor Freight.


-Fixed that for you.
grin2.gif



Harbor freight [censored]: $120
B&S 190cc at Equipatron: $150 plus shipping.

Win: B&S

Fixed it back for you.
grin.gif
 
Originally Posted By: 440Magnum


Harbor freight [censored]: $120
B&S 190cc at Equipatron: $150 plus shipping.

Win: B&S

Fixed it back for you.
grin.gif




HF- 25% off coupons and frequent sales = 79$--often
--currently $106$-- last week 79$

Equipatron = 159.97$

equipatron.jpg


updated. I see they just went off sale.
 
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Originally Posted By: 440Magnum
Never use a "heavy" flywheel engine on a mower, as that greatly increases the damage when you do hit a stump.


I think this is good advice. Many mower engines have heavy flywheels, like pressure washer engines, but they're usually used on mowers with blade brake clutches. My Honda HR215 and Lawn-Boy 8157 are such examples. The engine will sit there and idle all day long, without the blade turning. In fact, that's how you start them: without the blade turning.

But if a stump is hit and the blade does stop quick like, the blade clutch would probably soak up a lot of the momentum from the heavier flywheel. Without the blade clutch, I imagine that the crankshaft would be more prone to bending or twisting with the heavier flywheel's momentum.
 
Originally Posted By: Rand
Originally Posted By: 440Magnum


Harbor freight [censored]: $120
B&S 190cc at Equipatron: $150 plus shipping.

Win: B&S

Fixed it back for you.
grin.gif




HF- 25% off coupons and frequent sales = 79$--often
--currently $106$-- last week 79$

Equipatron = 159.97$

equipatron.jpg


updated. I see they just went off sale.


I'm sure that the Chondas do go on sale more often, I just think its more fair to compare standard prices against each other.

I know others have had OK luck with them, but personally until Hazard Fraught gets their "engine" down to $10 including tax and they pay me for my time installing that piece of slag, I'll pass.
laugh.gif
 
I can respect your point of view.

However on a 10 year old mower in unknown condition paying 70% the price of a new mower

is IMO a bad idea

sears has a whole new mower with that engine for 229-249$ (depending on options)

and the OP needs at least a new motor.. maybe new blade also?

might as well buy a whole new mower at that point imo.

on the other hand waiting on the every month 79$ chonda sale at HF he would be in for 79-100$ or so.
 
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Is it really going to hurt anybody to spend the extra money on a B&S engine over cheap Chinese junk? We need to protect our industries and that happens through consumer patriotism.
 
Originally Posted By: Silverado12
Is it really going to hurt anybody to spend the extra money on a B&S engine over cheap Chinese junk? We need to protect our industries and that happens through consumer patriotism.


Until I see those corps like B&S, Kohler, etc. brings back their assembly line and foundrys from china and re-start their assembly line on NA soil, otherwise: blind patriotism will ended up selling you down the river in the name of corporate profit.

Afterall: even with B&S flatheads which, up until a couple of years ago, over 80% domestically-built(except the carb which is a chinese made walbro LMS clone), B&S is gradually adopting to their new OHV "E" series due to tightening OPE emissions regulations and are all built in china.

Q.
 
Originally Posted By: Quest
Until I see those corps like B&S, Kohler, etc. brings back their assembly line and foundrys from china and re-start their assembly line on NA soil, otherwise: blind patriotism will ended up selling you down the river in the name of corporate profit.

Afterall: even with B&S flatheads which, up until a couple of years ago, over 80% domestically-built(except the carb which is a chinese made walbro LMS clone), B&S is gradually adopting to their new OHV "E" series due to tightening OPE emissions regulations and are all built in china.


Couldn't have said it better myself. If you're buying a cheap mower (maybe not a flathead, which are being phased out anyways), you're buying a Chinese made B&S engine. So who cares if you're getting a clone from HF or some cheap Chinese junk from B&S??

I was disgusted when I found out my $700 rear-tine roto-tiller had a Chinese made Briggs & Stratton 900 series (OHV). This is the same OHV Briggs engine that's been made for well over a decade. So the B&S being American is utter garbage in my opinion. I paid $700 for that tiller when the competing Toro's with Chonda engines were $550. The Chonda engines have a cast iron cylinder and ball-bearing supported crank. What does the Briggs engine on my tiller have? Aluminum cylinder wall and regular sleeve bearings for the crank.

In hindsight, I would have rather bought my tiller without an engine, equipped it with a Harbor Freight OHV engine, and still paid the same price-- AND BEEN AHEAD!!

Those that are stuck on Briggs and Stratton "Americanism" need to educate themselves fast. They (B&S) hide it so well in their model/serial numbers that you actually have to get someone online or by phone to answer for you where the engine was made--- Because the equipment manufacturer dictates where the product is made. For example [hypothetically!] your Toro lawnmotor is made in USA and advertised as such. What you don't know is that the B&S engine equipped on it is made in China. Completely invisible to you.

I had to literally find a B&S rep online that took these kinds of inquiries-- I gave them my model number and serial number (there's clues to country of origin if you're familiar with these engines, but not to the average consumer) and they came back with aluminum cylinder wall (that too is hidden in the serial no.), plain bearings (also hidden in said number), and made in China (I shouldn't have to state the obvious).
 
Originally Posted By: Silverado12
Is it really going to hurt anybody to spend the extra money on a B&S engine over cheap Chinese junk? We need to protect our industries and that happens through consumer patriotism.
Probably won't hurt anybody. But if there's no difference in performance,and it costs more, whats the point?. And being just about everything is made overseas theses days, the only thing made in this country is probably the box it comes in which gets thrown away.,,
 
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