Many questions on this engine.

[hooken203]

0G508602 1997 Mariner 150.
I bought this engine from a friend and it had very low compression on one cylinder. So I bought it as a project. Its a hobby a learning experience. What I am learning is this thing is going to break me before I am done. I also am learning all those things I told him had to be done as simple maintenance he didnt do any of it. Its no wonder it blew up.
I have the powerhead almost back together Just waiting on the last few parts to complete it.
Are surface gap spark plugs still the thing to use in this engine?
Thoughts on solid motor mounts? Factory replacements are 600 dollars Solids are half that. I have used solids in a couple Yamaha engines in the past. It did transfer more engine vibration into the boat but it wasn't that bad.
The exhaust plate had every gasket blown out and leaking the tuner was broken and almost ready to fall off. It has the long tuner in it. I have read that putting the shorter one in it will kill the bottom end. I have put different tuners in several engines and couldn't tell the difference. Again the shorter one is about half the cost. The engine is going on a light boat so I feel the loss of bottom end wont matter. Let me know your thoughts.

[lpugh]

0G508602 1997 Mariner 150.
I bought this engine from a friend and it had very low compression on one cylinder. So I bought it as a project. Its a hobby a learning experience. What I am learning is this thing is going to break me before I am done. I also am learning all those things I told him had to be done as simple maintenance he didnt do any of it. Its no wonder it blew up.
I have the powerhead almost back together Just waiting on the last few parts to complete it.
Are surface gap spark plugs still the thing to use in this engine?
Thoughts on solid motor mounts? Factory replacements are 600 dollars Solids are half that. I have used solids in a couple Yamaha engines in the past. It did transfer more engine vibration into the boat but it wasn't that bad.
The exhaust plate had every gasket blown out and leaking the tuner was broken and almost ready to fall off. It has the long tuner in it. I have read that putting the shorter one in it will kill the bottom end. I have put different tuners in several engines and couldn't tell the difference. Again the shorter one is about half the cost. The engine is going on a light boat so I feel the loss of bottom end wont matter. Let me know your thoughts.

use the surface gap plugs, resist fouling better, do not remove oil imjection
solid mounts may result in better handling, do vibrate more though, your call
Stock tuner for sure, would install carbon reeds though
consider having the heads milled a little, will require 91 octane fuel
Jay smith or chris carson for the head work

[JOE54]

stock tuner for sure , fuel curve is calibrated for it

[hooken203]

Thanks for your reply. My original intent was to rebuild and sell this engine. So I chose not to cut the heads. Everybody told me to scrap the oil injection. I won’t just for the convenience of it. And it has got this engine to the age it is without failure so it must not be that common of a problem. I would bet that most problems with the oil injection are caused buy pressure leaks in the system. It sure took me a while to get over the 350 dollar price of that oil pump but I ordered it the other day.

[hooken203]

Thanks Joe I hadn’t thought about how it may need a different fuel curve for the short tuner. Just that it is 100 dollars s cheaper.

[JOE54]

be sure you change the mixing check valve on bottom of vst as well

[silverbullet02]

I'd drop the oil injection like a bad habit. Depends on how heavy a boat it's going on as to which tuner to run, I've found they come plenty rich from the factory to be able to do a few mods and run great. Definitely stick with the surface gap plugs. Many who say they run better with the j-hook plugs are masking a problem, they run great with surface gaps when everything is working right. Yes on the solid mounts too for sure. Just my opinions.

[lpugh]

I'd drop the oil injection like a bad habit. Depends on how heavy a boat it's going on as to which tuner to run, I've found they come plenty rich from the factory to be able to do a few mods and run great. Definitely stick with the surface gap plugs. Many who say they run better with the j-hook plugs are masking a problem, they run great with surface gaps when everything is working right. Yes on the solid mounts too for sure. Just my opinions.

On a fishin boat keep the oil injection, I see more problems with it eliminated than I see with it

[hooken203]

Would you use the solid aluminum mounts or the Delrin mounts?

[lpugh]

Delrin for me

[JOE54]

^^^^^^+1

[hooken203]

Joe did you see those pictures of the piston an cylinder I emailed?

[JOE54]

yes sir i did

[hooken203]

Here is another one. As I said above the tuner was broken and about to fall off. The holes in the plate that let water to the tuner are plugged with small pebbles. Would you open up these holes slightly so they don’t plug and burn up the tuner?

[JOE54]

yes in sandy areas for sure

[hooken203]

Thank you for your help Joe. Are you getting those big storms down there? Stay safe.

[JOE54]

it hells in my shop every day