Mariner 115 2+2. Bottom plug fouled

[Kgonefishin]

Folks,<br /><br />The bottom plug on my Mariner 115 2+2 keeps getting fouled with fuel. When the motor reaches about 2000 RPM the motor starts to shake. The compression and spark are good according to the marina. They have run SeaFoam through the motor, checked the High end stator, and checked timing with inductive light. They also installed a carb rebuild kit. The mechanic does not think the fuel pump is the problem but I'm not sure he tested it. The tech from Merc is sending them a valve - I think it is called a restrictor valve - to install. These guys have had the boat for 2 1/2 weeks and are just guessing at this point.<br /><br />Drydocked in OH.

 

[Clams Canino]

Re: Mariner 115 2+2. Bottom plug fouled

No idea here.... but you can bet they'll try to charge you for all the "experiments" on the way to finding the $20 problem.<br /><br />And people call me a dinosaur when I say the 115 was perfected in 1988??<br /><br />-W

 

[WillyBWright]

Re: Mariner 115 2+2. Bottom plug fouled

That motor WILL stumble and shake at those RPMs. Between about 1800 and 2200, the motor will jump between running on 2, 3, and 4 cylinders. That is by far the biggest complaint about those motors and there's nothing anybody will be able to do about it for you. It's an inherent characteristic of that motor. If you absolutely MUST run at 2000 RPMs, you'll want a different motor because you won't be able to with that one. Below 1800 and above 2200 they run just fine. It's that range inbetween that causes people fits. Make sure that dealer is a Merc dealer with Certified mechanics. Dealers that work primarily on other brands might not be up to speed on this subject and could be wasting your time and money.

 

[Kgonefishin]

Re: Mariner 115 2+2. Bottom plug fouled

Thanks for the reply. If I have to live with the shaking, I will, but the real problem they have not been able to solve is the bottom plug getting fouled with fuel. The boat, when it is running properly, should hit 47MPH WOT. We were only able to get it to hit 30MPH. They are a Mercury certified dealer. I'm not sure that the mechanic is certified. If anyone in the Cleveland area knows of a top-rate mechanic that can work on the 2+2, please let me know.<br /><br />Thanks,<br />Mike