Black scuff marks on cylinder walls

[mertkajosh]

I see very little carbon on the Pistons Crowns. If the Rings are have Tension and spring back when pushed, the Grooves are likely free of Carbon.
How long have you had this Motor?

I just bought it last year. So maybe 9 months

 

[mertkajosh]

Gee, the pictures of the pistons look brand new. Carbon is minimal, IMO. Clean the water jacket if she needs it, install new head and transfer cover gaskets and go boating.

I also thought the pistons looked pretty new. I hope everything works out

 

[racerone]

Evidence suggests that this motor may have a lot of hours on it.-----What condition is the lower unit in?

 

[mertkajosh]

Evidence suggests that this motor may have a lot of hours on it.-----What condition is the lower unit in?

It looks fairly new. Most lower units I’ve seen have paint missing from going through sand and water. This one has never lost a flake of paint anywhere. I bought it from a guy that had it on a pontoon. They used it in a no wake lake. So that may be why the lower unit is in such good shape

 

[mertkajosh]

Evidence suggests that this motor may have a lot of hours on it.-----What condition is the lower unit in?

It honestly looks like the motor has ever hardly been used. I mean the paint is all nice. Under the cowling everything is clean. I’m baffled with the way the cylinder walls look

 

[racerone]

The way I see it.----This powerhead was rebuilt with 0.020" O/S pistons.----It failed again.-----Then it was taken apart again.---Cylinders were given a quick honing ( ball hone ? ) and assembled.----A ball hone might hide the score marks.-----After running the score marks show up again.-----What do the deflectors ( water diverters ) look like in the water jackets?----And is the serial # on the powerhead the same as the number on the midsection?

 

[mertkajosh]

I will check all that when I get home. The deflectors were clean. No debris what so ever or sand or what not.

 

[jimmbo]

It honestly looks like the motor has ever hardly been used. I mean the paint is all nice. Under the cowling everything is clean. I’m baffled with the way the cylinder walls look

Fresh Paint can hide a Multitude of Sins
As Racer has said, it has been rebuilt, I wouldn't be surprised if those Rings were reused, if they were, they would have fit the earlier Scoring, and are trying to duplicate it on the newer Bore
One of the Ports does appear to have what looks like Ring Damage.

 

[ct1762@gmail.com]

I see very little carbon on the Pistons Crowns. If the Rings are have Tension and spring back when pushed, the Grooves are likely free of Carbon.
How long have you had this Motor?

yes but im just saying while its apart cant hurt to get a jump on it. we all know how quickly carbon can build on these!

 

[jimmbo]

Actually, with the use of a Good TCW-3 Oil, and the engine properly Propped, Carbon Buildup is quite Low and Slow

 

[racerone]

There is nothing wrong with some black stuff on the top of the piston.

 

[mertkajosh]

Fresh Paint can hide a Multitude of Sins
As Racer has said, it has been rebuilt, I wouldn't be surprised if those Rings were reused, if they were, they would have fit the earlier Scoring, and are trying to duplicate it on the newer Bore
One of the Ports does appear to have what looks like Ring Damage.

Do you think the motor is toast?

 

[racerone]

Just run it and hope for the best.

 

[jimmbo]

Do you think the motor is toast?

Not yet. If the scoring doesn't get too bad, it likely can be machined to 30 thousands overbore, so as racer says just run it, might last several yrs....

 

[mertkajosh]

Not yet. If the scoring doesn't get too bad, it likely can be machined to 30 thousands overbore, so as racer says just run it, might last several yrs....

Thank you for all your help!

 

[mertkajosh]

Just run it and hope for the best.

Thank you for all your help!

 

[mertkajosh]

The way I see it.----This powerhead was rebuilt with 0.020" O/S pistons.----It failed again.-----Then it was taken apart again.---Cylinders were given a quick honing ( ball hone ? ) and assembled.----A ball hone might hide the score marks.-----After running the score marks show up again.-----What do the deflectors ( water diverters ) look like in the water jackets?----And is the serial # on the powerhead the same as the number on the midsection?

The serial number of the powerhead matches the serial number on the midsection.

 

[Mc Tool]

The way I see it.----This powerhead was rebuilt with 0.020" O/S pistons.----It failed again.-----Then it was taken apart again.---Cylinders were given a quick honing ( ball hone ? ) and assembled.----A ball hone might hide the score marks.-----After running the score marks show up again.-----What do the deflectors ( water diverters ) look like in the water jackets?----And is the serial # on the powerhead the same as the number on the midsection?

Yeah , I could go for that but I think the pistons and rings are in to good a condition to have been involved in a serious damage to a cylinder wall event , who knows ?

 

[mertkajosh]

Yeah , I could go for that but I think the pistons and rings are in to good a condition to have been involved in a serious damage to a cylinder wall event , who knows ?

I removed the bolts holding the powerhead on and burnt oil started flowing from the holes. Is this from a bad base gasket?

 

[racerone]

Use a factory replacement gasket.---Best quality