speckula

I believe shop manuals will tell you to mount the motor with the cavitation plate inline with the bottom of the boat. However, you can mount it up a notch. By doing this you will gain some top end speed but lose some handling when the motor is trimmed up. As stated before, if the motor is trimmed down in turns you shouldn't have a problem.

Also, if you mount it higher, the boat will not plane as quickly and it may porpoise, even when trimmed all the way down. Since you have raised it, try it out. But if you notice handling, porpoising or planing issues that you don't like, lower it back down.

I raised mine a notch and I did notice more top end and a lighter bow, but I have trim tabs and it really isn't a problem.

bullet175

Speckula wrote

"Also, if you mount it higher, the boat will not plane as quickly and it may porpoise, even when trimmed all the way down. Since you have raised it, try it out. But if you notice handling, porpoising or planing issues that you don't like, lower it back down."

OK I was able to take the boat out this weekend. Longer planing times and porposing was the results of raising the motor for me. Just as soon as started to trim up it would start to bounce so Ill be putting back where it was to start.

But Ive encountered another problem that I cant say whether or not was present before I raised the motor or is a result of me raising the motor.

We went out of venice and headed out the southwest pass of the river. It was a long run and the longest strait run Ive made so far in the boat. Motor runs real good for about 15 mins. into the run and then starts to surge just as if you cut the key off for a split second. It keeps doing this until you throttle back. After that itll run good again for a while and then starts to surge again. Also hitting waves like a boats wake will set off the surging. after I drive over the first wave and come into the next one a surge willhappen and itll do it on the rest of the waves. Each surge is the same as the last and they happen with about a 1 second frequency.

I dont think Ive raised the motor enough to cavitate and get on the rev limiter?

I was thinking it might be a fuel delivery problem. A clogged filter would be nice. When I got home I took the cowl off and noticed the motors fuel filter was almost empty of fuel. I removed the screw on filter in the bilge and noticed it was only about 1/2 full of gas. And no gas came out of the lines when I unscrewed it. I blew air through the motors filter and its free. Ill be putting a new screw on filter in tomorow. I have yet to check the tanks filter.

Am I on the right track or am I barking up the wrong tree.

Tuna Man

Sounds like you are on target...check tank pick up and for any place air can be sucked into the system (tank fittings, line fittings etc).

Lil Skeet

Check your tank vent, primer bulb, and check valve between fuel tank and engine if you have one. Many people do away with those check valves.

bullet175

Hey skeet. The tank vent was another possibility Ive considered. My fuel fill pipe and the tank vent both come into the fuel fill and vent via the cap. I will be checking that too. As far as the one way valve goes....well I broke it off trying to get it out... so much for it. I was wondering of I could replace it with a regular barbed fitting. I guess I will now. You answered my next question before I even asked it. Thanks for the info. When I pulled the fuel pickup out of the tank the tube was good and the filter was clear. So far I havent found any leakes or blockages.