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Swapping engine shafts


hgiljr's Avatar
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FL

01-27-14, 03:43 AM   #1  
Swapping engine shafts

Good day. I have a spare Briggs Stratton engine with a 7/8 vertical shaft. My lawn mower engine has a 1inch vertical shaft. I would like to swap engine as my the lawn mower engine is giving me problems and the spare engine which came from a pressure washer works just fine, both craftsman's machines, main difference is the shaft. Can I replace the spare engine shaft with the lawn mower shaft to perform this engine swap? Thanks for any feedback given.

 
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Pilot Dane's Avatar
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01-27-14, 05:15 AM   #2  
You did not provide any information about your lawn mower's engine. Is it even a Briggs? I'm afraid you'll have to post the manufacturer's name and model numbers for both engines for anyone to even have a chance of knowing if the shafts can be swapped.

Have you considered using a shaft adapter bushing? I don't know if they make them thin enough to only go up 1/8" but it would be a whole lot easier than tearing two engines apart to swap cranks.


 
sidny's Avatar
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01-27-14, 07:21 AM   #3  
The shafts

Ty some of those old lawnmower shops that you see along the roadsides, and you might get lucky, and find the right coupling for your 7/8 shaft. Is worth a shot.
Sid

 
hgiljr's Avatar
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01-27-14, 05:05 PM   #4  
Yes both are Briggs Stratton engines on Craftsman equipment. The engine with the 7/8 shaft is on the pressure cleaner and the 1 inch is on the lawn mower. Pressure Cleaner Sears model number is 580.752070 and Lawn mower is 917.370561. Not sure the Briggs models, will have to get back to you on this.

As for the shafts, worth a try. I will see what I can find. Thanks again

 
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01-29-14, 01:13 PM   #5  
Engine shafts have to have the same dimensions to work in a separate engine or it will cause a major failure. Most engine enthusiast's lives would be much easier if it were easily swapped but Briggs' cranks are not.

You may need a Crankshaft Dimensions booklet to help you figure out if your Cranks are compatible or not. Here is a website where you can download it...

Briggs Crankshaft Dimensions Guide E-book Download Briggs And Stratton;download Crankshaft;crankshafts Guide;briggs Crankshaft Dimensions

 
sidny's Avatar
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01-29-14, 01:50 PM   #6  
The shafts

I forgot to mention in the earlier post, that right away if the shaft size changes,e.g.
3/4 to 7/8 the crank case bearing size changes also.
Sid

 
cheese's Avatar
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01-29-14, 06:36 PM   #7  
I don't think I ever saw one where the crankcase bearing size changes when the crankshaft pto size changes 1/8". The crankshaft is one size going through the block, then it is turned down to whichever size needed.


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sidny's Avatar
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01-30-14, 05:05 AM   #8  
The shafts

Got it Cheese, thanks.
Sid

 
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