'88 Yamaha 115 with a dead cyl.

[Part-time]

I have a 1988 V-4 and the bottom starboard side cylinder has low compresion.
The head has been removed and from what I can see the cylinder is going to be ok with just a good honing. The piston has some damage on the exhaust port side.
Can I remove that piston by simply removing the carbs/intake or do I have to split the block?

 

[Part-time]

pics

pics

 

[Part-time]

Well, if anyone else runs into this... the cases have to be split.

 

[72rude]

Re: '88 Yamaha 115 with a dead cyl.

I have an 84 115hp. Everytime I ran the motor last season it seemed to overheat after a minute of 75% throttle. Power dogged out completely but would continue to run and have enough power to troll. I shut it down for about a half an hour, it started back up, ran for 20 seconds and won't start. Starboard pics below ... head has no severe damage. That one piston does have some.Any advice for a first timer?

 

[99yam40]

Re: '88 Yamaha 115 with a dead cyl.

http://forums.iboats.com/announcement.php?f=26

 

[Part-time]

Re: '88 Yamaha 115 with a dead cyl.

72rude, that's what mine looked like from the head as well.
this is what I'm into now... I had to remove the powerhead and split the case to get the pistons out.
I need to replace 3 of the 4 pistons so I'm probably going to get it bored over and 4 new pistons and rings.
Looks like you might be expecting the same thing.

#2 was the only good one, #1 and #4 have scored pistons but the jugs could be fine with a light honing and #3's rings are stuck and although the piston is badly scored the jug could get away with a good honing but I'm thinking of just going .030 over all the way around.

 

[72rude]

Re: '88 Yamaha 115 with a dead cyl.

72rude, that's what mine looked like from the head as well.
this is what I'm into now... I had to remove the powerhead and split the case to get the pistons out.
I need to replace 3 of the 4 pistons so I'm probably going to get it bored over and 4 new pistons and rings.
Looks like you might be expecting the same thing.

#2 was the only good one, #1 and #4 have scored pistons but the jugs could be fine with a light honing and #3's rings are stuck and although the piston is badly scored the jug could get away with a good honing but I'm thinking of just going .030 over all the way around.

Much appreciated PT, sorry about the hack ... I'm new here.

 

[Part-time]

Re: '88 Yamaha 115 with a dead cyl.

Much appreciated PT, sorry about the hack ... I'm new here.

Hey, no problem.
This yamaha thing is all new to me as well and I'm just figuring it out by myself as I go along.
If this thread can help just one person at least I know my time wasn't wasted putting it up.
Now that I found what is broken I have to find what broke it in the first place...
I'll update when I get there.
Let me know what you find when you go digging into your motor 72.

 

[four4fish]

Re: '88 Yamaha 115 with a dead cyl.

hi guys. friend of mine is asking me to help with 1988 yamaha 115 with a dead cylinder . want to try to just hone and rering. from what you are running into doesnt look like its going to work . how far along are you guys into it and do you think its worth it? thanks joe

 

[Part-time]

Re: '88 Yamaha 115 with a dead cyl.

I honed all 4 holes and replaced the 2 starboard pistons and rings.
I have 125 to 130 psi in all 4 holes now... and it cost me around $400 - $450 for the pistons, rings, seals and gaskets to put her back together.
For sure I would have rather put everything new while I was in there but lack of funds prevented me, and I am quite satisfied with the end result.
At least this way I was able to get her back on the water!

And take pictures of both sides of the motor BEFORE you start ripping things apart!!!

 

[four4fish]

Re: '88 Yamaha 115 with a dead cyl.

Thanks that doesnt sound too bad. Who did you use for parts and is there any where you looked for special info, or just the factory service manual . and how long to tear down and reassemble? thanks joe

 

[Part-time]

Re: '88 Yamaha 115 with a dead cyl.

I used aftermarket. I got them at the Yamaha dealer but the parts were sierra.
It's pretty straight forward. Take pictures so you remember where to run the oil injection lines and wiring.
Put it back together the same way you took it apart (mark/number parts if necessary) and the torque specs and tightening sequences are on the block.
The only thing is you need metric tools and the only special tool required is a 12 point 10mm socket to remove the bolts from the bearing caps on the connecting rods.

 

[99yam40]

Re: '88 Yamaha 115 with a dead cyl.

did you take care of the lean condition or overheat that caused problem?
If not it will happen again