Sv150 engine very hard to turn over with recoil

[mikerecike]

Running a self propelled mower.released drive cable to take pressure off.not hydro locked -plug off and pulled over several times. Could a stuck valve cause this? Runs fine when fires - havent checked for bent crank but doesnt vibrate like mad?not sure how to access valves in this.its a honda knock off found on mountfields,champions etc.cheers folks.feels like seized/very high compression but runs fine when fired.

[2stroke-ady]

Is there something wrong with the brake mechanism? I take you have the opc pulled in!

[mikerecike]

Is there something wrong with the brake mechanism? I take you have the opc pulled in!

 

Ok brake is something to check ady - opc fully engaged at handle. Thinking about it - its very stiff then you overcome resistance with brute force then seems to pull ok till you hit that resistance spot again -gonna break recoil if im not careful

[2stroke-ady]

Has the coil come loose and sticking to the magnets. Dead easy to whip the top off and have a look.

[GardenKit]

This sounds like compression, it could be that the decompressor is not working.

Is it OK with the plug out?

[Rich2484]

I'm sure I've got one of these in the lockup as a project mower.

 

As Barrie said take the plug out and see if it changes.

[2stroke-ady]

Blade loose?

[mikerecike]

No change with plug out - so that rules out valve/decomp mechanism? will check coil tonight ady. Dont think its blade - not kickback just really stuck. Havent seen a pic or vid of the inside of an sv150 engine . I remember barrie you pointed out to me the decomp lobe on the briggs classic cam.is this the same set up? Cheers folks.

[GardenKit]

TBH Mike, I have never been inside an SV150 to see the decomp, and there are no IPL,s for the engine internals, or any info on engine internals in the w/s manual. The engines are so cheap that they are just replaced if they fail under warranty, and if outside warranty its cheaper to dump the mower and buy new.

 

But, back to yours.

If the tightness still exists with the plug out then its not compression related.

Its going to be mechanical.

So off with the recoil cover, (as has been said already) and check the proximity of the ign module to the flywheel. Also check the brake arm functionality.

 

If its all OK up top then it just could be damaged valve gear. If so you are not going to repair it, but you could quickly take off the head and observe the valves. You might find excessive carbon build up between the piston and the head, which could be the problem, if so you could scrape it off and stick the head back on (if the gasket is OK) and try it.

 

But I sort of think that you may have a bent crank, bent just inside the engine bottom plate. Once again, you wont be repairing that, but you could take off the sump plate to check.

 

Have fun and let us know the outcome.

[Rich2484]

just out of interest could you flip it up and just turn the blade by hand. check its not the deck tht is bent and catching the edge of the blade.