9.9 Mariner Tweeks?

[savage]

On older motors you could change carb, but on a 94 I don't think you can do anything. Wait for Corm to reply.

 

[Bubba]

9.9 Mariner Tweeks?

I have a '94 Mariner 9.9 and wanted to know if there are any tweeks that can be done to increase performance, like the carb and exhaust changes on the Johnson and Evinrudes, for the Mariner.

 

[corm]

Re: 9.9 Mariner Tweeks?

Hi Bubba,<br />Sorry, all you can do is trade it for a 15HP.<br />Your motor is 12.8 cu inches. The 15 is a 16<br />cu inch motor, so it is a whole different block. The OMC motors are both 13.2 cu inch<br />blocks, so parts interchange.OMC also revs the 15 another 750 RPMs to get the HP. Where as the Mariner's both run at 6000 max RPM. If<br />you need more power,try a smaller prop.Every inch in pitch will change the RPM 150 RPMs.<br />I don't know what boat it's on, but a stingray mounted on the cavitation plate would give you more tail lift. To plane faster and make the boat run flater. One other thing, most 8-25 HP Mercs and Mariners<br />I see mounted on boats are mounted to low.<br />The cavitation plate should be no more than 1/2 inch below the bottom of the boat.If yours is low add a wood shim to the top of the transom to raise the motor within specs.<br />Then BOLT the motor to the boat sealing the bolt holes, so their are no leaks. Even the smaller motors can slide off in a hard turn.<br /><br />...have fun...corm