# Tracker jon boat/motor issue



## k4jns (Jun 8, 2015)

I have a 15x42 Tracker Jon boat I bought new last year. I installed a 9.9 Johnson on it and noticed a issue where if I turned hard left I would get the spun prop effect, I marked it and took it back out. Off with the prop and everything still lined up. So last year I just dealt with the issue by not turning hard left issue solved. Well about a month ago I bought a 35 hp Johnson. Took some time to have a shop go threw the lower unit so it would pass a pressure test and got it back last week. Long story short I took it out Friday and had the same issue only it happens when going strait once on plane. Off with the prop marked it took it back out. Checked it, lines still lined up so I ruled a spun prob out again. Now I'm puzzled, The bottom of the boat lines up with the cavitation plate and when I was out I tried all the trim settings with no luck at all. Seems like the best setting is the one closest to the transom. Still I noticed right before it happens I'm planed out and increasing throttle to a little over half way. The cavition plate is pretty much even with the water line. I'm not sure if this is really normal but it almost seems like the motor is mounted to high because you can almost see the prop before it skips and starts reving up higher in RPMs. Seems really weird to have two different motors with the same type issue. Am I over looking something? The transom is strait on the top where the motor mounts I've noticed some are cut kinda like this ------\____/------- At this point I'm lost and really dont know what to try next. Ideas and advice would be greatly appreciated.


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## overboard (Jun 8, 2015)

Short shaft motors, on a long shaft transom ?????
That would make it look like the motor is mounted too high.


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## k4jns (Jun 8, 2015)

Transom measures 16 3/4. Everything looks right I just measured the top of the mount to the cavition plate which turned out to be 16.5.


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## Charger25 (Jun 9, 2015)

sounds like its " blowing out' in turns. I not a big fan those fins ,but in your case I think it would help keep the prop hooked up.


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## k4jns (Jun 9, 2015)

What do u mean hooked up?


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## SumDumGuy (Jun 9, 2015)

k4jns said:


> What do u mean hooked up?



He's saying that a hydrofoil may keep the prop from ventilating.

hooked up meaning to have water to push as opposed to air.


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## RiverBottomOutdoors (Jun 9, 2015)

Sounds like motor mounted to high or not trimmed right.


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## Skiffing (Jun 9, 2015)

It could also be a bump or depression in the hull close to the stern. Is it nice and flat back there? Even 1/4" can make a difference.

An option is a jack plate. Pushing the engine back a few inches allows it to be higher in relation to the hull.


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## k4jns (Jun 9, 2015)

Its strait but the bottom of the boat has five ridges running from the front to back the length of the boat.... Like for water to sit in I guess... There about a inch deep could that be it?


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## Skiffing (Jun 9, 2015)

Those are strakes.

I'm talking about a bump or depression parallel to the beam.

There's a special word for it - someone here will know.


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## richg99 (Jun 9, 2015)

If you are talking about a "hook in the hull" (ridge or bulge at the stern)....a hook will cause the bow to stay down when getting up on plane. Some manufacturers actually design them in, on purpose. I don't think a hook would cause what the OP is describing.

Blowing out, which is what I think the OP is describing, could be anything from too much power during the turning; the wrong prop; motor too high...and on and on.

Certainly a Doel type fin MIGHT keep water on the prop, but they have other negatives...and might not work at all.

I don't know anything about proper propping, but I'd talk to a good prop shop if I were the OP.

regards, richg99


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## overboard (Jun 10, 2015)

Post a pic. showing the motor and the bottom of the transom, maybe someone can spot the problem.


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## muddywaders (Jun 10, 2015)

A big enough dent in the bottom of your hull will cause ventilation.16 3/4" is a bit high for a shortshaft.Did someone add material to the the transom?Is it possible to lower it without cutting?If not you may need a bracket or Jackplate.I have done some experimenting with motor height and found that the highest position before it just starts to ventilate will yield the highest speeds.Even one inch of length will slow the boat.Not sure of the physics but it must be something other than just the extra resistance of a small piece of midsection below the waterline.


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## k4jns (Jun 11, 2015)

Maybe these pictures will help? I cant figure it out hand hate to go buying stuff if im not even sure it will help.


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## Charger25 (Jun 11, 2015)

looks like it too high in the top pic. If the transom has not been altered,you're gonna need a jack plate to set motor back or a some kind of bracket to lower it some


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## k4jns (Jun 11, 2015)

No it hasn't been altered its all there with factory welds I bought the boat new. So I'm not understanding how I'm suppose to drop the motor?


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## muddywaders (Jun 11, 2015)

k4 search this site for images of jackplates and you will see that it will allow height adjustment up and down.You may have remove or shorten clamping screws but you should be able to lower it a few inches without having clearance issues.Another solution would be to buy a longshaft parts motor swap out the shaft and mid section and raise your transom.Cheaper just to make up a jackplate.An aftermarket powertrim unit like a cmc mounted a bit lower may work as well.If you do make a plate make sure the tiller bracket and front of motor will clear transom when tilted up.Good luck mw


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## Ictalurus (Jun 11, 2015)

Having a hard time with the pics you posted. In the first, it looks like the cav plate is about an inch higher than the bottom of the boat, although the level appears crooked. The second pic looks like your setup is just about right.

So the question, in the first pic, is the level straight with the bottom of the boat? If so, your cav plate is high. If you build/buy a jackplate you shouldn't have to lower the motor as you can increase motor height with additional setback.


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## Skiffing (Jun 11, 2015)

You're engine is too high - perhaps as much as a couple of inches.


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## k4jns (Jun 12, 2015)

In the second picture i agree it looks fine. In the first one, the level is strait with the bottom of the boat. When in the water it looks like the "jet" from the prop is facing up when at full speed not level either. I guess what i'm trying to say is the wake from the prop comes up like three foot from the back of the boat in a up ward direction if that makes since. If i was to convert it to a long shaft it would be way to low I believe. I've had many boats and have never noticed this. I did some reading and they say the tracker's transom is vertical rather then at any type of angle. I have no clue as to how a jack plate really works? What do I need to buy?


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## Charger25 (Jun 12, 2015)

Perhaps something like this, it can be used to raise or lower the motor. just to give ya an idea


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## k4jns (Jun 12, 2015)

See in the picture u posted it showed the cav plate really higher then the bottom of the transom. Is that ok with the motor back farther? I'm sorry I'm just trying to get a better understanding. I was looking at something like this mini jacker https://www.basspro.com/MiniJacker-for-Clampon-Outboards/product/8782/ but its not adjustable like I really think it needs to be. I honestly don't want to spend a crazy amount of money. I saw some on ebay also that are adjustable in the 150 price range.


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## k4jns (Jun 12, 2015)

Maybe something more like this? https://www.vancemfg.com/untitled12.html


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## richg99 (Jun 12, 2015)

Well, I sure wouldn't just go buying jack plates ( I've owned a few); Doel fins; Smart Tabs (great product) or any other add-ons until you have a real handle on what the problem and solution is.

From your original post, I thought it was blowing out while turning quickly.

There must be a Tracker's forum someplace. You need to find a group of owners who have experienced exactly your issue, with your same boat and motor combination. Then, you need to find out what THEIR solution was to that exact same issue. Only then would it make sense to buy something IMHO.

All of these add-ons solve problems, in one way or another. None of them solve ALL problems. As I said before, you may need nothing more than some cup added to your prop. 

richg99

p.s. If the issue was that the tracker transoms were too vertical, they sell wedges that will tilt your engine to a more normal slant. I doubt that will do anything for you....but???

p.p.s. Here are a couple of Tracker boat forums'

https://forums.iboats.com/forum/owners-groups-by-manufacturer/t_z/tracker-boats

https://www.ultimatebass.com/bass-fishing-forum/index.php?board=493.0

https://www.thebassholes.com/bassin-forums/182-tracker/13532-tracker-owners.html


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## k4jns (Jun 12, 2015)

It started out with blowing out on sharp left turns. But the I've swapped to a 35 hp motor that's started doing the same type thing only when going strait at high rpm. I just went and talked to a a friend that builds off shore race boats and he's going to look at in Monday but the first thing he said was get that motor down lower and that he's seen things like this happen with flat bottoms.


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## Skiffing (Jun 13, 2015)

k4jns said:


> See in the picture u posted it showed the cav plate really higher then the bottom of the transom. Is that ok with the motor back farther? I'm sorry I'm just trying to get a better understanding. I was looking at something like this mini jacker https://www.basspro.com/MiniJacker-for-Clampon-Outboards/product/8782/ but its not adjustable like I really think it needs to be. I honestly don't want to spend a crazy amount of money. I saw some on ebay also that are adjustable in the 150 price range.



Yes.

Underway the water will swell after the boat passes right? That water is higher then when exiting from beneath the hull.

Therefore, your engine can be higher when it is on a jackplate further away from the transom.

With your 35HP you are ventilating at high RPM because the prop is losing grab on the water when the hull planes down. When the hull planes down the transom is effectively raised.

Your prop may be under-pitched as well - which will contribute to the problem - but the fact remains your engine is too high.

When I was adjusting my jackplate [see thread in my signature] I raised the engine about an inch higher from where it worked fine. The result was ventilation at WOT unless the water was like glass. A little chop and it would ventilate.

I lowered it back an inch and everything has been fine.

I'm running a 16' V @ 1250 lbs loaded w/ a 40HP and a 14" x13 pitch prop. ~ 28mph WOT.


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## k4jns (Jun 14, 2015)

I'm going to do some further testing this week. This is what I have been tossing around in my mind. 1- this happened with the 9.9 motor when turned hard left with me sitting on left side of the boat. 2- With the 35 hp this doesn't happen when it's just me in the boat. But does happen when I have me and another person and gear = weight. I'm starting to think maybe it could be the weight making the boat sit lower. Which means the cav plate could be to low? I made some shims to play with so maybe I can bring the motor up a hair for testing with the type of weight in the boat again. Either way its either the motor is to high or to low. Looking at pictures of cav plates when the boat is moving I see most don't have water on them just splashing them when at WOT. I'm starting to thing I might have been looking at this the wrong way. I'll get it out there and do some testing to figure out what I exactly need to do either way I believe a jack plate is going to be the answer obviously.


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