Blown piston on 86 Mercury 200 Black Max

[tsimpson-az]

I just bought a 1986 Ranger 393V with a Merc 200 Black Max. I pulled the heads and one of the pistons is blown (I'm guessing). It has pitting around the piston edge and on the head around the edge. The cylinder wall is pretty scratched too so I assume the ring must have melted. The other 5 pistons all look good. I am wondering if this is repairable or not. If so can I repair just the one cylinder or do I have to do all of them or do I have to replace the whole power head. Trying to decide if its worth repairing or scrapping for parts.

I have photos I took of it but not sure if I can post those here or not.

Thanks for any guidance here.

 

[j_martin]

Re: Blown piston on 86 Mercury 200 Black Max

If it hasn't shoved a rod out the side, it's repairable. Even some with a leg out of bed are repairable. It's probably worth it. One bore can be repaired, or re-sleeved without doing them all.

Ya tear it down and see what needs to be replaced to put it in top shape.

hope it helps
John

 

[Faztbullet]

Re: Blown piston on 86 Mercury 200 Black Max

Thats a chrome bore motor and it will have to be sleeved to repair any damage to cylinder walls...

 

[Orbit Express]

Re: Blown piston on 86 Mercury 200 Black Max

tsimpson
Sound to me someone got you good. Typical problem with these Merc's. Why didn't you ask the seller to start it up, or maybe take you for a ride, (oh, he did). Do you know if the boat leaks? Best thing to do is probably make a lawn ornament out of it, and buy a real outboard, look into a Evinrude.

 

[starcraft1982]

Re: Blown piston on 86 Mercury 200 Black Max

orbit,dont jump to the conclusion that he got taken.Maybe he was aware that the motor had "issues" and got it for a very good price,expecting a rebuild or re-power.(us merc. guys use our heads like that).what I wouldnt suggest is getting on a merc area and bashing them.And i definately wouldnt advise anyone to re-power w/a sevond rate outboard!

 

[Faztbullet]

Re: Blown piston on 86 Mercury 200 Black Max

Yep dont jump on that Junkrude wagon to quick as I can post of pic's of the E-tecs with holes punched thru the sides....

 

[CharlieB]

Re: Blown piston on 86 Mercury 200 Black Max

What is the compression on that hole?

Post the pictures or a link to another photo hosting site.

Pull the exhaust cover so you can see, feel the rings, take another picture.

 

[Dukedog]

Re: Blown piston on 86 Mercury 200 Black Max

tsimpson
Sound to me someone got you good. Typical problem with these Merc's. Why didn't you ask the seller to start it up, or maybe take you for a ride, (oh, he did). Do you know if the boat leaks? Best thing to do is probably make a lawn ornament out of it, and buy a real outboard, look into a Evinrude.

Evin"RUDE"......BLAWAAAAAHAHA!!!!!!!!!!!!!!!

 

[tsimpson-az]

Re: Blown piston on 86 Mercury 200 Black Max

Thanks for all of the feedback guys, although with so many opinions it's hard to decide what to do. I think I did get taken, or actually my wife. She bought it at an aution for what seemed a low price but she never pulled the engine cover or she would have seen the head bolts were already loose. BUMMER! Now I got to decide if I should repair the motor, replace the motor or just sell all the "good stuff" separately and try to recover some money. By the way I don't see any other visual damage like a rod sticking out. I guess I will tear it down and see what it looks like internally. I have not taken any compression readings. I will try to post pictures later tonight.

 

[tsimpson-az]

Re: Blown piston on 86 Mercury 200 Black Max

Ok here are the pictures, if they post properly.

 

[Orbit Express]

Re: Blown piston on 86 Mercury 200 Black Max

Looks like bearings between crank and piston rod let go, found their way into combustion head - new powerhead required.

 

[CharlieB]

Re: Blown piston on 86 Mercury 200 Black Max

Once you get it apart and see what the crank and rod look like you will have a much better idea and can start adding up repair costs.

If hurt, the crank can be repaired, Outboard Crank Service is one place I can recommend, there are a number of others. Do NOT take the crank to an automotive crankshop!!!!!

Rod, piston and a chromebore cyl liner are all readily available.

This engine can be saved quite reasonably or used as an exchange on a warrantied rebuilt powerhead.

 

[tsimpson-az]

Re: Blown piston on 86 Mercury 200 Black Max

Once you get it apart and see what the crank and rod look like you will have a much better idea and can start adding up repair costs.

If hurt, the crank can be repaired, Outboard Crank Service is one place I can recommend, there are a number of others. Do NOT take the crank to an automotive crankshop!!!!!

Rod, piston and a chromebore cyl liner are all readily available.

This engine can be saved quite reasonably or used as an exchange on a warrantied rebuilt powerhead.

Thanks for the info. Any recommendations on where to get a rebuilt powerhead?

 

[sschefer]

Re: Blown piston on 86 Mercury 200 Black Max

Unless that's trick photography that's #6 that leaned out. It looks to be a sleeve in that cylinder but it also looks like it's just aluminum stuck on the walls so it should clean up with a hone IF you have the right equipment. If this is your first motor and you don't intend for outboard repair to be your hobby for life then send it out.

 

[rodbolt]

Re: Blown piston on 86 Mercury 200 Black Max

if its a chrome bore and you hone it the bore is junk.
if the chrome isnt scratched use muratic acid,carefully, to remove the aluminium from the bore.
merc used to offer a rechroming service or you can resleeve it and use cast iron bore piston and ring sets.

 

[CVX20SPRINT]

Re: Blown piston on 86 Mercury 200 Black Max

Looks like bearings between crank and piston rod let go, found their way into combustion head - new powerhead required.

Looks more like pieces of ring stuck in the head to me,not bearings.I would continue the tear down if it was mine.If the bearings were gone there would most likely be a rod hanging out somewhere.

 

[tsimpson-az]

Re: Blown piston on 86 Mercury 200 Black Max

Unless that's trick photography that's #6 that leaned out. It looks to be a sleeve in that cylinder but it also looks like it's just aluminum stuck on the walls so it should clean up with a hone IF you have the right equipment. If this is your first motor and you don't intend for outboard repair to be your hobby for life then send it out.

I am a pretty good car mechanic but have never worked on an outboard so I would take it to a shop for that. I'm not sure if it is number 6 or not, but it is the lower, left cylinder looking at the engine from the back.

Thanks for the info.

 

[Faztbullet]

Re: Blown piston on 86 Mercury 200 Black Max

No sleeve it that hole and that cylinder will need sleeved. There are several crank repair companys but OCC (Outboard Crank Service/company ) has been out of business for 4 years. I wont even build a 2.4 chrome bore anymore as there are to many 2.5 liter blocks on the market to replace it.