Author Topic: boat bouncing (Read 682 times)

sprig · « **on:** November 13, 2003, 03:08:37 PM »

i have a 17' express with 90 hp 4 stroke yamaha if i trim it all the way out it goes to bouncing. anybody got any suggestions?

1911crazy · « **Reply #1 on:** November 13, 2003, 04:31:13 PM »

I found two very good bassboat sites; bassboat.com and bassboatcentral.com there are owners reviews on boat setups too.
BigBill

Skipper · « **Reply #2 on:** November 14, 2003, 04:01:43 AM »

Its called porposing, and no, contrary to what you'll hear, you probably can't drive through it.

Your best bet is to tuck the engine a litte to plant the bow just a little. That should stop it. There's no reason to trim an outboard all the way out. First off, you have a tendancy to dry pump the water pump when you do that because you get the intake too high out of the water. Secondly, after enough trimming, you get the thrust going the wrong way, up instead of out.

If you are having trouble winding your engine up to full song, Its probably a safe bet that you need to go to a smaller prop.

Skipper

sprig · « **Reply #3 on:** December 02, 2003, 01:33:22 PM »

I FIXED IT. i took 2 trim tabs that you would normally put on your lower unit to prevent counter tourquing. and ground the back of them to 1/8 0f an inch and welded them to the 2nd step on back of boat next to pad. no more porporsing. runs great.