Mariner 175 EFI Rebuild

[Skeetin']

Hey guys,
Looking for some insight on rebuilding my 94 175 efi. Top starboard piston is gone. Im looking to rebuild my powerhead and want to get some info on where to buy a rebuild kit and who offers the best one. Also wanted to talk about which brand pistons would be best and if it would be worth the upgrade for forged pistons? I know there are a lot of veterans here and good information. Thanks in advance guys.

 

[wired247]

Re: Mariner 175 EFI Rebuild

If you are talking about Wiseco's, they arent an upgrade. Unless you are twisting it over 8000 RPM there is no need to run forged pistons and even then Wiseco's arent on any race outboard builders go to list. Why? They need to go through multiple heat soak cycles before they stabilize and even then they really only work well with nikasil bore motors unless you run with a LOT of clearance to keep them from swelling faster than the bore opens up when the motor gets hot. You arent going to twist a 175 that fast anyway. Better to use cast pistons in a sub 8K motor. There are a number of suppliers of aftermarket pistons and other goodies that will help your motor run better and go faster. Chris Carson Marine has helped me out a lot in the past with good pricing and good parts. You can also get good parts on iboats ( don't crap on your hosts website ) It all depends on how much you want to spend and how fast you want to go. A little exhaust chest work, a light bore job, new pistons, bearings and gaskets, shaved heads, fiberglass reeds and some attention to detail can work wonders.

First things first. You smoked a piston for a reason. Fix that problem. Have your injectors professionally cleaned.

 

[Skeetin']

Re: Mariner 175 EFI Rebuild

Thanks wired. Alot of good info there. Im not looking to make any extra power or race my bass boat down the water, just want to get to the fishing hole and back. lol. A definite positive on having my injectors checked out/ cleaned. Ive read quite a few threads about rebuilds where people have trouble with that top right cylinder. On top of that, i will be taking the oil injection off and running straight premix. I purchased the boat with the motor blown so I knew what i was getting into. I will check out Carson Marine and iBoats, weigh out my options. I dont mind spending the money now if it will keep me from spending more later down the road.