Trouble planing out

[Mully]

Friend has 18' Lund Pro-V. He had a Yammi 100 4 stroke on the transom and he just replace it with a 150 Yammi 4 stroke. Here is the problem...

The boat performed OK with the lower horse power motor. It took a little time to get on plane with the boat loaded but overall it performed well. He wanted more power and finally bit the bullet and put the 150 4 stroke on.

The boat will not plane out. His dealer is recommending small fixes, i.e. lift tabs, etc. but he believed that there is something more to it. How can a more powerful motor not plane out? My friend believed that it may be the cables or throttle assembly (if there is such a thing) that were not changed when the larger motor was installed. He is at a loss. He is going to take the boat out and check rpms and keep a log on performance to tell his dealer.

He has owned boats before so he knows how to set the power trim, etc.

Any suggestions?

[Hot Runr Guy]

The rpm's check should tell what going on, but it sounds like the dealer put too high of a pitch prop on to start with. Any idea what prop is on it? Sure, the new F150 may be 100# more than the old F100, but it should certainly get that hull moving.
HRG

[staylor]

Its easy to check and see if the throttle is full open. Pull the cowling, pull the kill switch, and with boat on trailer have someone spin the prop clockwise from the rear while shifter is moved to FWD gear. Then find the intake butterfly or the throttle linkage under the cowling and see if it opens nearly to the stops when the throttle is pushed to full open position. If its opening fully, its not the linkage/cables. The rpm check is the next way to go, as the dealer may have simply put on a prop with way too much pitch. The added tabs will help with hole shot, but I agree with you that since the boat was OK with the smaller motor then going to the 150 should not mean that you need to add tabs to plane. Something is screwed up.
Doug

[Mully]

Thanks for the quick responses. My friend had a few adult beverages when he was filling me in on his dilema and he didn't remember the pitch of his prop. I will print your recommendation Doug since you are speaking in an unknown language (intelligent) and pass it on.

Thanks