81 200HP Evinrude- no compression in #4 cyl

[KANSAS GOLD RUSH]

Had a comp check done on this engine, #4 is zero,other 5 range from 110 to 125.Mechanic said it could be a number of things. I'm thinking rebuild. Have owned the thing since 88 with no problems.Pulled a lot of skiers on an 81 20ft glastron carlson.Is the engine tired? Can i check for broken ring without total tear down or is there anything else to check?

 

[Joe Reeves]

Re: 81 200HP Evinrude- no compression in #4 cyl

Kansas.... Remove the cylinder head to inspect the piston and related cylinder.

 

[KANSAS GOLD RUSH]

Re: 81 200HP Evinrude- no compression in #4 cyl

Pulled head, foreign object damage to piston and head. Can 1 piston be replaced without total teardown of powerhead

 

[kenthrussell]

Re: 81 200HP Evinrude- no compression in #4 cyl

bad news you will have to tear it down .perhaps a reed valve got sucked in that would have caused the damage.............I am selling a ski boat a 17.5 foot panther with a 200hp merc v-6 1987 rebuilt powerhead and compression on all 6 are 124-125 after about 30 hrs running and working good.it also has a jack plate and bottom water pickup,have already bought a 27foot century so this boat has to go want 6,000 firm canadian for the whole package......let me know if you didn't want the boat you could sell it less the motor and put the engine on yours. love my ski boat but wife does not like it wants the comfort i guess<br />e-mail ken.thrussell@sympatico.ca

 

[BKool68]

Re: 81 200HP Evinrude- no compression in #4 cyl

Yes you can replace just one hole without removing the crank and other pistons if only the one cylinder needs light honing. check the other cylinders to be certain they are not scored up. New rings for all is not much more expense. If you had a bearing failure more work might be necessary.

 

[Joe Reeves]

Re: 81 200HP Evinrude- no compression in #4 cyl

Kansas..... Unfortunately, regardless of what must be replaced within the powerhead (one wrist pin, whatever), the entire powerhead must be completely dismantled in order to do the repair/rebuild properly. Otherwise it would be quite easy to overlook one particle of foreign material or faulty part which would lead right into a repeat performance.

 

[KANSAS GOLD RUSH]

Re: 81 200HP Evinrude- no compression in #4 cyl

Ok,I want to know if I can pull the powerhead while it's still fully dressed (everything on it- carbs- flywheel, ect). I am looking in my Seloc manual and it tells me nothing about how to do that. Is my first time tearing into one

 

[KCLOST]

Re: 81 200HP Evinrude- no compression in #4 cyl

This is a good question Kansas, I'm wondering the same thing about my 50hp Merc. At least this will bump the topic to the top..... What do you have to watch out for when you pull the powerhead, gears, springs, gaskets, etc....?<br /><br />Let's see....

 

[BKool68]

Re: 81 200HP Evinrude- no compression in #4 cyl

It can be removed complete if you wish. You will have to disconnect fuel and oil lines, cooling hoses, shift and throttle linkage, electrical connections to harness and battery, and the screw that connects the shift rod under the carbs to the linkage. There are no springs or gears to deal with, just a gasket that will be stuck solid and the drive shaft from your lower unit. Removing some parts first will reduce the weight of motor and the risk of damaging something ( carbs or linkage) when you are trying to seperate and lift the motor off.

 

[KCLOST]

Re: 81 200HP Evinrude- no compression in #4 cyl

BK is right,<br />Diffinitely remove the screw that holds on the shift cable to the whole linkage mess...<br />Also remove the throttle mess. That should be done easily by only removing one bolt. Do this before you remove the head or even move it off its base.<br /><br />The electrical stuff and gas line is all you need to worry about after that, especially if you need to remove it entirely off. Do that ahead also...<br />I learned this the hard way...