73.5 gps at 5500?(stopped looking) and out of control

[aaronmt]

I just got back from the lake and it hit 73.5 with no winshield or back seat in yet im hoping thats whats making it chine walk so bad. It is not safe at 73.5. I have the motor all the way up and i think i could use even more setback. Am i right to be think that the more setback i run the less height i can get out of the jackplate? I dont like the idea of stacking 2" spacers but i feel i do need more , anyone make 4inch spacers? And at what point does it start to look goofy? Boat is as light as it can get Ill be putting the rear seat back in and the widshield this weekend. Any i deas guys on the setback ? thanks Aaron

[illMATTic]

sounds good. has that prop been worked at all? the rpms sound a bit low for that speed. could your tach be off?

you will have to learn how to run through that walking. once you do you will find the true top speed of that boat.

i dont know if adding more than 12" setback will do anything. do you have to trim up past 0 deg. right now?

[F150GT]

Nice numbers. The more set back you add the higher you need to raise the engine. The angle of the transome is not 90 degrees to the bottom of the keel, so the farther you go back the lower the engine gets, This also holds true for the amount of trim and bow rise you have(the higher the bow gets, the deeper the engine goes). Also as you go back farther the curl of the water gets higher the farther back you go. I played around with some excessive set back and the engine heights we were running is extreme.
For adding more set back I would get a piece of 4" alluminum square tubeing and place it between the transome and your jack plate. You can stager the holes in the 4" to get your jack plate higher and I cut the tubeing extra long so it will extend down the transome farther, this helps distribute the load on the transome over more surface area. There is a picture of my Enchanter set back in "Picture this" in my F150GT file.
The transomes are NOT strong enough for this much set back withought reinforcing and bracing, be carefull.
F150GT

[boatman4021]

Hey Aaron, Sounds like that extra hole made a big difference! Sorry I missed your call, but I have been on the go all day. Trying to finish moving, working on other peoples boats, delivering props, and trying to finish rigging my boat. What a day! My suggestion to you now would be to get some seat time and learn how to drive through the chine walk. Once you do, you will handle the boat without even thinking about it. I would say you are very close to the sweet spot, but when running above 70mph, you are going to have to drive the boat. Any thing I can do, just let me know. boatman

[175checkmate]

The other thing I would look at is weight distribution, or more to the point. Where the weight is located. Try filling some small bags with sand and moving them around in the boat. If it was just you in the boat then the balance is off on the starboard side.

[Mark]

I just got back from the lake and it hit 73.5 with no winshield or back seat in yet im hoping thats whats making it chine walk so bad. It is not safe at 73.5. I have the motor all the way up and i think i could use even more setback. Am i right to be think that the more setback i run the less height i can get out of the jackplate? I dont like the idea of stacking 2" spacers but i feel i do need more , anyone make 4inch spacers? And at what point does it start to look goofy? Boat is as light as it can get Ill be putting the rear seat back in and the widshield this weekend. Any i deas guys on the setback ? thanks Aaron

Congrats, you're running with the big boys now! You might want to check your tach thou because 5500 rpm with a 25" prop and 73.5 mph is minus 5% slip. You are actually turning well over 6000 rpm if your GPS speed is correct.

[aaronmt]

I will be putting the interior back in tommorow. Im wondering if not haveing the windshield on or the back seat could in be a problem. I was thinking that the wind comeing over the bow at these speeds and going back into where the seat is normally at could be causing some of the handling problems. A question i do have is on the steering how do i tightren it up it is the teleflex nfb dual cable steering(new). There is no grease fittings i see at all what do i do for that. Thanks for all the suuport Aaron:thumb:

[JW]

Make sure the cables are turned against each other with a little tension at the motor end to help with steering chine walk issues. You'll never be able to get rid of the chine walk until you also remove the rubber motor mounts and install solid mounts.......................

[aaronmt]

Just got back from the lake with the windshield on, boat handles alot better. I wasnt able to get any numbers, but i also had my gf with me an shes NOT OK:shakehead: with learning to drive through the chine walk with her in it. The winshield on made quite a difference the chine walk has lessond considerbaly. I will be put the rear seet in tommorow and hopefully get some action photos when she gets off work. I will also be looking at how to adjust the cables more. Thanks Aaron Jw what do you meen turned against eachother? thanks Aaron

[Mark]

It's not the windshield that made it handle better, it's the girlfriend! A person in the passenger seat makes all the difference in the world since it balances the boat.
If you do not have dual cable steering there is really not much to adjust. Just make sure everything is as snug as possible with no slop.
As JW said, if the chine walk is a big deal for you, you need to bite the bullet and install solid motor mounts.

[illMATTic]

my boat is all over the place if i have only myself in it. take someone other than your girl next time.

[aaronmt]

Ive ran the boat with a buddy in in without the windshield and the chine walking was there so the gf was the same as before. But i do think with the windshield in it directs the air over the boat better instead of into the void where the back should be(itll be in tommorow). I will be checking and rechecking the steering, any ideas on how to lube this there is no zircs its a teleflex nfb dual steering. Can i install a zirc in the tubes that cables go through on the motor? Thanks Aaron.

[Mark]

Bob's machine sells a nut with a grease fitting that goes on the tilt tube. It will keep the water out of the cable if greased regularily.