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Engine help please

#1

Dscag2021

Dscag2021

Hey all, I have a scag 52” prov, 19hp Kawasaki fh580v giving me a little trouble, starts fine second pull, when I go to engage blades, the power drops significantly, like it’s straining, and stays like that. It’s my home mower, I bought it used a few years ago, I change plugs and filters and oil yearly.


#2

StarTech

StarTech

Most likely it has dropped a cylinder.


#3

Scrubcadet10

Scrubcadet10

fire it up.
and pull one spark plug wire off at a time... If you pull the left one off and it dies completely. the right side one is the culprit, and vice versa.


#4

Dscag2021

Dscag2021

Ugh, I’ll try that


#5

Dscag2021

Dscag2021

Better to rebuild or go with new engine?


#6

Scrubcadet10

Scrubcadet10

It could be as simple as replacing either a bad spark plug, or ignition coil... once you determine the dead cylinder, i would check for spark on that cylinder with an inline spark tester.


#7

Dscag2021

Dscag2021

Ok, looking at machine from front of deck, I removed the spark plug on right , machine died. Left side removal it stayed running.


#8

Scrubcadet10

Scrubcadet10

Left side is dead. remove the spark plug from the left side, reinstall the wire on it, and ground the tip of it to the engine (metal) and check for spark.


#9

Dscag2021

Dscag2021

Oh there’s spark lol


#10

Dscag2021

Dscag2021

Dscag2021 said:
Thank you’s for your help , now gotta find a small engine repair place in ct
Click to expand...


#11

cpurvis

cpurvis

Remove the valve cover from the dead cylinder and see that both valves are operating properly.


#12

Dscag2021

Dscag2021

Idk, I know my limits, I don’t have a backup mower to try something I never done on this one, if I stood next to someone and handed them wrenches and was able to watch, I’d be more confident


#13

cpurvis

cpurvis

Then take it to a shop.


#14

Dscag2021

Dscag2021

Yup, ugh


#15

T

txmowman

Sounds like a failed ignition coil. A coil can produce a spark but not have the energy to fire the cylinder under compression.


#16

Dscag2021

Dscag2021

What would make engine smoke? Because it smokes now


#17

Dscag2021

Dscag2021

StarTech said:
Most likely it has dropped a cylinder.
Click to expand...
I did a compression test, one side has about 80-90lbs and the other side doesn’t. I’d say you’re correct. What would next step be?


#18

H

hlw49

Not a good way to test for spark U need a 1/4 inch gap to simulate ign. firing under compression. In his first test the plug was bad see all the black crud on the plug that was unburned oil and it acts as insulation that is the reason the spark was jumping to the body of the plug which did indicate a good ign. system since it was probably jumping a 1/4 inch gap.


#19

Dscag2021

Dscag2021

hlw49 said:
Not a good way to test for spark U need a 1/4 inch gap to simulate ign. firing under compression. In his first test the plug was bad see all the black crud on the plug that was unburned oil and it acts as insulation that is the reason the spark was jumping to the body of the plug which did indicate a good ign. system since it was probably jumping a 1/4 inch gap.
Click to expand...
One spark plug was cleaner than the other if that means anything


#20

H

hlw49

U say one cylinder has 80-90 psi compression and and the other has none? Determine why you have no compression check and see if the piston is moving up and down. Take the plug out and stick something down into the cylinder and turn it over by hand. If it is moving up and down then it sounds like it would be valve related. If not then it probably threw a rod. The FH580V is an old engine and those things had a propensity to wear the top main bearing out. Unless you know a good machinist it is not fixable. Post the spec. no. and someone can tell you if there is a replacement engine for it.


#21

Dscag2021

Dscag2021

Thanks, when I get a moment I’ll go check.


#22

S

slomo

Valve stuck open from valve seat lifted out of the block.
Rocker arms slash valve clearance all out of whack.
Never cleaned the carbon from the cylinders as required in your engine manual.
Never cleaned the cooling fins, again, in your engine manual.


#23

Dscag2021

Dscag2021

cpurvis said:
Remove the valve cover from the dead cylinder and see that both valves are operating properly.
Click to expand...
Ok, removed the valve cover. The pushrod was not seated in bottom rocker. And while trying to attach the pushrod ,the stud snapped that the rocker is attached to. I ordered a new stud, new nut , and hex screw


#24

H

hlw49

Might look at the valve guide to make sure it has not backed out. Is the push rod bent as well.


#25

Dscag2021

Dscag2021

hlw49 said:
Might look at the valve guide to make sure it has not backed out. Is the push rod bent as well.
Click to expand...
Pushrod rolls smooth


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