[PA318Guy]

I repaired my B&S engine on my sprayer last year and today it was working good then I look back today spraying and I'm not getting full rpms to the sprayer pump and the shaft from the engine to the pump is sort of just twitching around. Turn the eingine off (it was running just fine) and I could spin the shaft freely by hand. Doesn't this come off the crankshaft? Before and after shots below. Also I used it last year with no problems other than I had to replace the magneto.

 

[k91]

Pictures of the shaft in question?

 

[PA318Guy]

The end of the crankshaft broke off. Cleanest break I've ever seen! No idea what caused it because it was lined up perfectly with the the pump.

 

[k91]

Well now you know whats wrong :fing32:

 

[PA318Guy]

Crankshaft is $82.50, new engine is $200 - $260.....hmmmm!

 

[k91]

HF engine time

 

[PA318Guy]

Just got off the phone with the neighbor, he had the same engine in his junk pile and he's going to give it to me! Free crankshaft just have to tear it down! Just got back and his was 5 hp so it's either order the new crankshaft or get a different engine.

 

[RedOctobyr]

Just got back and his was 5 hp so it's either order the new crankshaft or get a different engine.

... or have Sprayer 2.0, Now With 67% More Power

 

[PA318Guy]

pump takes a 5/8 inch shaft, 5 HP has 3/4 inch shaft. Looking at HF I'll have to go with the 79cc engine due to shaft size too. I don't think that will be an issue since the motor is not working to turn that pump.

 

[PA318Guy]

Now I have a perfectly running 3 HP engine without a shaft!!!!:thSick::thSick::thSick::thSick::thSick::thSick::thSick:

 

[CADplans]

The rebuilt engine will be good for when you just need to be outside and HEAR an engine run!! :fing32:

That is a real :fing20:

Can the coupling to the pump be changed to 3/4"?

I used to use one of those, I switched to the 12 volt electric pump for putting down 2-4-D.

 

[RedOctobyr]

Could you put some sort of adapter on the crankshaft of the 5hp engine, to take it down to 5/8?

If you were going to pull the crankshaft anyhow, I wonder if you could weld the broken part back on, depending on where it broke. Being realistic, probably not. Even if you got it welded on, it likely wouldn't be perfectly concentric & parallel with the rest of the shaft. Making it just more likely to break again.

 

[PA318Guy]

Mount on the sprayer doesn't give any extra room to mount an adapter between shaft and pump.

I thought about having it welded but a new engine from HF is only $99.00 so that is likely the route I'll take. I will probaby strip down my engine and put it on ebay for sale minus the crankshaft.

 

[tomw0]

I would be concerned with pump-crankshaft alignment. A slight mis-alignment will put a load on the shaft with every revolution. Thought it took a long time, you ended up with a stress fracture likely caused by that force. If possible, when you mount the new powerplant, I'd fit one of the couplers that allows for a bit of mis-alignment. I've seen them on hydraulic pumps on log splitters. Wonder if they make them with different sizes such that a 1" PTO can be reduced to what you need by the coupler.
tom

 

[RedOctobyr]

+1. Any alignment or parallelism issue will stress the crankshaft with every rotation, building up a lot of fatigue cycles quickly. An appropriate coupling, if it's feasible, would help avoid suddenly looking for *another* replacement engine in 6 months or whatever.