Is this bad?

[Pussiwillow]

I had my cylinder head off my 15 hp Johnson cuz I had a low compression issue, warped head took .015 off the head and .005 off the block, when I had it off both cylinders had scoring, felt smooth to the touch and I took my finger nail to them and maybe got hung on 1 or 2 score marks but not very deep, I'll try to include a pic, I finished it and my compression gauge was reading 40 pound both cylinders, took it to local mechanic and got 135 both cylinders on his gauge, but the score marks have had me thinking and was just curious as the motor runs like a beast, no issues just curious if it's normal is all thanks

 

[1946Zephyr]

Re: Is this bad?

well, score marks are not good. That motor must have over heated in the past, since your head was a little warped. Since you got 135 psi on each cylinder and each are even, then you're fine to run it like that. I would run it 24:1 to give it a little better lubrication on those pistons.

 

[Pussiwillow]

I'm almost certain this motor overheated before I bought it, there's no problems with the motor just been a little bugged lately about the cylinders looking like that, I don't know why as it runs great but it had me thinking if it was normal for cylinders on these engine look like that near exhaust ports, 24:1? Would I need different plugs? I'm asking cuz I'm weary about fouling plugs, would this be an issue?

 

[kfa4303]

Re: Is this bad?

24:1 with Champion J6C plugs should be just right. You shouldn't have an issues with fouling. I ran the same combo in my old '61 10 hp, and I just got home from the lake idling and zooming around all day with the same combo in my '66 20 hp with no issues. Virtually no smoke either.

 

[1946Zephyr]

Re: Is this bad?

Well, the plugs should handle the extra oil fine. The extra oil will help the pistons, since they scored up a bit.

 

[Pussiwillow]

Hey sounds great I'm gonna mix it up 24:1 on my next run, could the scoring been caused by carbon through the years getting broken down and grinding against the piston and cylinders? The scoring is so light, they felt so smooth and are only visible near the exhaust ports and not all the way around the cylinder

 

[boobie]

Re: Is this bad?

Don't worry, just run it.

 

[1946Zephyr]

Re: Is this bad?

Yea, since you have 135 psi in each cylinder, your rings are working fine. I would just run it.

 

[F_R]

Re: Is this bad?

If anything, the scored pistons may affect the slow idle.

 

[jerryjerry05]

Re: Is this bad?

My dad had a 60hpV4 from 1968.He ran it till 97 then repowered.
He took off the heads and all the cylinders looked like that.
Great comp.ran great (gas hog).Sold it and I know it still ran after 8 more years then I moved away.

 

[ENSIGN]

Re: Is this bad?

Those hash marks on the cylinder walls are suposed to be there,they help lubricate the cylinder.135 pounds of compression is fine just ru it.