boat points toward sky before planing.

healey8390

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I had a 78 wellcraft airslot 165 with a 90 chrysler and it got on plane great. The boat was in bad shape but I love the model so much I bought the same one, a couple years older, a 75'. Found a great deal on a motor and got a 86' Johnsin 110.

Boat hauls ass and goes 42 where the other boat only went 33. The problem is that this boat has a very hard time getting in plane and I don't know why since it's literally the same model.

TBS a lot of water did drain out after the trip, I'm thinking it was rain water hiding below. But if it was enough water to make it point up why did I top out so fast? Also,I noticed that the inner hull seems ro be foamed to a certain exten. Can foam water log? I hope not because I'll be SOL. Lastly, do those hydrofoil fins help as much as they're advertised? Thoughts please.
 

Scott Danforth

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back off on the prop pitch. your going faster because you have more motor, however I expect it is propped for speed and not the holeshot.

you may want to move some weight forward.

and water in the boat is not a good thing.
 

healey8390

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I was a test trip so I din't fwwl like hooking up the tach, I just wanted to get out there.I'm gonna hook it up for the next trip so I can see if I need to re-pitch.

Think the water snuck up on me because of the angle of my driveway. It didn't look lije there was any in there. Next time I'll put the plug in at the ramp so any exess will drain. I really hope it's the water.

On a positive note I can't beleive 20HP would gain that much speed. I have always been a Chrysler "supporter" because they're soo easy to work on and are reliable IMO but I did hear they aren't as powerful as their similar HP counterparts. Now I know this is true. Chrysler was an 83' 4cyl 90 fwiw.
 

jbcurt00

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Your Chrysler was likely a crank rated OB and the 1986 is a prop rated OB so there's more then a 20hp jump between them, perhaps more then 30hp. Change was in early 80's and the re-rating HAD to be done at the prop by 1985, IIRC.....

So that'd be about a third jump in hp from the 90hp, which is a lot, IMO. But it looks like you're still under max HP, 120+/- right?
 

healey8390

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From what I heard they went to prop ratings in 83 so Chrysler rebagged their 105 as a 90. All previous 90hp chryslers were 3 cyls. TBS the tect of chrysler was always outdated, from porting to possibly gear ratiis so I think you're onto something wuth a 30+ hp increase. Also, my Johnson is a bubble back!

The max hp for the boat us 120 So I'm good.
 

thumpar

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Jun 21, 2007
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Does the motor have power trim? The trim setting has a lot to do with how fast you get on plane and then how fast you can go. If it is not down/in then the motor is pushing the nose up. You don't want that when trying to get on plane. You do want it when on plane for max speed.
 

WrenchHead

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I added the hydrofoil fins to my 60 HP Merc. I'm running a Bass Tracker 175 which I bought as a package. The fins did make a slight difference. The big difference I see from the fins is when cruising at about 2,000 RPM and then go to WOT. Then the boat takes off like it's on a clothes line.
 

pckeen

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Foam can waterlog, but if it was just sitting there due to rain for a couple of day's, I wouldnt be too worried. If the water sat there for a lengthy period of time, you may have a problem. What prop do you have on that motor?
 

Chris1956

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The bow will rise a lot if the motor is trimmed up too much. Usually you start with the trim pin in the second hole from the transom. It can be adjusted down if necessary.

If you have PTT, then remove the pin and trim down.
 

healey8390

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It has t&t, I went in and it didnt help at all.

It has a stainless prop, I'm not sure of the brand/pitch.

I'm hoping it was the water but since it was the first trip my gears started turning about possibilities. Hopefully I can get it out this weekend.
 

Scott Danforth

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assuming that your running the correct length outboard and the motor is set up properly, with power tilt and trim, go all-the way in and hit the throttle, when the boat climbs out of the hole, start trimming up.

however if you have a long-shaft motor on a short transom, you will always climb toward the sky during the holeshot.
 

Texasmark

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I'll go with the water too and a channel in the bilge allowing it to move around fast. The minute you hit the throttle it all goes to the stern and there is your problem I'll bet. I agree with all the other posters on things they mentioned but I'd do as you plan to do, drain the bilge first.

Mark
 

Maclin

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There should be an adjustable pin location on the transom mount for the all-in setting, where the engine mount hits the transom mount. Maybe someone was experimenting and left it out a ways and you are not really getting all-in on the trim.
 

healey8390

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Thanks to everyone for your replies. I checked the pin and it's al the way in.

Took it out yesterday and didn't put the drain plug in untill I got off my driveway and a lot of water came out. TBS it still did it but not quite as bad so the water was a factor but it wasn't the main cause. I experimented and took off faster an it helped a little but I don't want to have to gun it ro get on plane. I'm gonna get a hydrofoil. I seen one that claims to decrease plane time by 50%, increase fuel economy and top speed. We'll see!
 

Texasmark

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Thanks to everyone for your replies. I checked the pin and it's al the way in.

Took it out yesterday and didn't put the drain plug in untill I got off my driveway and a lot of water came out. TBS it still did it but not quite as bad so the water was a factor but it wasn't the main cause. I experimented and took off faster an it helped a little but I don't want to have to gun it ro get on plane. I'm gonna get a hydrofoil. I seen one that claims to decrease plane time by 50%, increase fuel economy and top speed. We'll see!



What's wrong with gunning it to get on plane? The worst stress the engine sees, besides initial starting, is getting on plane. The faster you move through that area the better. Besides, once you get over the hump and the bow starts coming down, you can back off the throttle and feather it to whatever speed you choose to travel. I'll tell you this. If I were behind you on skis and you pxxxyfooted around with the throttle, I'd smack you when I got back in the boat!

Mark
 

healey8390

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What's wrong with gunning it to get on plane? The worst stress the engine sees, besides initial starting, is getting on plane. The faster you move through that area the better. Besides, once you get over the hump and the bow starts coming down, you can back off the throttle and feather it to whatever speed you choose to travel. I'll tell you this. If I were behind you on skis and you pxxxyfooted around with the throttle, I'd smack you when I got back in the boat!

Mark

Lol I'l be sure to stay on it if we go water skiing.

The problem is it's so bad, once I let off or WOT or near WOT it loses plane. I was doing some more reading and I'm really thinking it's the prop. From what I read cup and rake can affect bow lift. The prop is cupped pretty good and the motor came off a smaller bass boat so I'm thinking they have it cupped and raked for bow lift. I'm gonna take it in but I really need to put the tach in so I can see what my rps are first.
 

Chris1956

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Wait a minute....you have a 16.5 footer with a 110HP motor, and you need to run WOT (i.e near 42MPH) just to stay on plane? There is something wrong there, as a boat should plane by 25MPH, which would be 1/2 throttle or so.
 

Bondo

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Ayuh,.... Try puttin' a 6' straight edge up against the bottom of the hull, on the keel line,....

The 1st 4" oughta be Flat, 'n True,.....

I'm guessin' yer gonna see daylight 'tween the bar, 'n hull, showin' a Hog,.....
That'll screw up yer hulls Attitude,....
 

healey8390

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Nov 19, 2010
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215
Wait a minute....you have a 16.5 footer with a 110HP motor, and you need to run WOT (i.e near 42MPH) just to stay on plane? There is something wrong there, as a boat should plane by 25MPH, which would be 1/2 throttle or so.

I'm sorry but I didn't word that right, was exaggerated. It feels like just off WOT because I don't have to move the throttle much to lower my speed but for sure it stays on plane at 30.

It's like the motor sucks the rear of the hull into the water, never seen anything like it. The other boat didn't ever do this and it was 20hp less, probably more of a gap given the tech difference between the two. Keeping fingers crossed it's the prop.
 

Texasmark

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Dec 20, 2005
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How about a side picture taken about 4' from the side of the boat with the camera even in elevation with the keel. Interested in seeing the bottom of the boat as it approaches the transom, the engine height as measured by the antiventilation plate vs the bottom of the boat, the tilt of the engine, and a side shot of the prop. If you can't get all that into a picture at 4' then take 2 pictures side by side to include all that. Would surely help us in resolving this.

Mark
 
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