motor mounting position 90hp force

[A.Hoj]

Ok now that I have the motor runnning again, I want to mess around with the mounting height.

The boat is an 18' CC steury thats pretty heavy and deep vee-d, and the motor is a 90hp Force 1998. Seems a little slow to me with only 28mph top speed, I know the prop may be part of the issue.

Right now the bottom of the cavitation plate is about 3/4" below the Keel (see pictures) I have an arrow taped to the bottom of the cavitation plate to show the height better.



I've read that the bottom of the cavitation plate should be even with the keel, and also that it should be 1.5" above the keel line. So my question is whats the best mounting height. Right now the motor is mounted with the bolts in the top holes so I have plenty of room to move up. I belive the holes are about 3/4" apart. go up one hole or two?

Thanks

 

[droach77]

Re: motor mounting position 90hp force

I had the same problem on my boat and i went 2 holes. Its really easy to do lower the the front of the trailer, put some wood blocking under the skeg and then raise the front of the trailer to take the weight off. I used an air hammer to knock the bolts out, then just raise the front of the trailer up until your holes line up , caulk the bolt shanks up really good , tighten back down and your done. I noticed a big difference on my boat. BTW if you go to the merc website and search for rigging it shows you all the good stuff. GOOD LUCK


dave

 

[Frank Acampora]

Re: motor mounting position 90hp force

Different engines react differently on different hulls. You need to experiment. FIRST be certain you have the correct prop. Then, Raise the engine one hole at a time and test. When you get to the point where it ventilates on the straight, lower it one hole. Then remove the bolts one at a time and coat them and the holes with sealer and rebolt them.

 

[jerryjerry05]

Re: motor mounting position 90hp force

http://www.onlineoutboards.com/index.html Look here.