4 HP 91' Mariner needs rebuild -is it worth fixing?

[jplomeo]

Hi ,

I have 1991 4-HP Mariner kicker used for trolling. Last year it overheatad due to water pump failure (my fault-should have replaced sooner). Replaced pump and new head gasket and lower power head gasket but engine still ran rough (lots of smoke and sometimes have to have choke partially open). Rebuilt carb and fuel pump. No change. Took it in to marine shop and they tell me compression is too low (80 instead of 150). Cost to rebuild is $500 parts & labor.
How difficult is it to rebuild or replace the piston rings- is it even worth it or should I look for another kicker?
Thanks in advance
JP

 

[Sunfish12]

Re: 4 HP 91' Mariner needs rebuild -is it worth fixing?

It's worth it if you can do the work, not worth it to have shop do it.

 

[Maxz695]

Re: 4 HP 91' Mariner needs rebuild -is it worth fixing?

you can hone the cylinder walls i belive up to 3 thousandths of an inch before having to put oversized ring in. get cutting oil and a cylinder hone a good drill and a micromiter to measure from tightest cylinder portin usaualy the bottom of the cylinder. subtracct the widest part and you,ll know what you have to work with at that point you goal is 3 thousandths from the original bore not from cylinder wear point. get specs for your engine. Just like honing a master cylinder or wheel cylinder. make sure you have something to catch all the metal that might get in the motor hone facing with the cylinder facing down or dismantle the pistons rings conecting rod etc before honing. If at the top of the cylinder just where the farthest point of the top ring you can feel a ridge than that would more than likely be the most worn section you may wat to measure this point to find out your total wear. if it,s below 3 000ths than get a rige reemer and remove the ridge before honing the cylinder out

 

[jplomeo]

Re: 4 HP 91' Mariner needs rebuild -is it worth fixing?

Thanks much for the info, but it looks like I may have to go looking for a new motor . Water pump and carb rebuild I can do, but taking out the piston, replacing rings and boring out cylinder is way past my expertise.
Thank you again very much
JP