Does this outboard look set up correctly.

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driz

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I got this boat as a project 2 years ago and used it for one season. It porpoised badly unless trimmed full down. It also acted quite badly in the handling department. I blamed it much on wet foam but upon tear down it wasn't that wet. The motor is an 83 4 cyl Merc 50 the boat is an 85 Tracker Tournament V17. Of course there are no jacks on this boat just power trim. It's mounted fully down on the transom and has been that way a long time I believe. So based on these pics....Motor trimmed full down, do you see any obvious reason it is prone to acting like Flipper on crack. #-o What it had on it originally I have no idea. Note, the pics look like the motor is hitting the back trailer roller but it's not, that's full down......about where that thing likes to run IIRC.
 

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I advise to see if wearing right prop 1st, then if OB is mounted properly for that prop 2nd ... before you try other things 3rd.

PROP - Check your prop diameter and pitch, for that exact motor and hull (and load/gear routinely carried), here: https://forum.tinboats.net/viewtopic.php?f=4&t=37433 If your hull is not listed, find a suitable alternate make that fits your specs.

HEIGHT - This is arguably the BEST post (IMHO) ever written on checking and confirming OB mount height - https://www.veradoclub.com/index.php?topic=137.0

HULL - You could have a 'rocker' in the hull that is causing that porpoising. You have ample motor HP, so the LU angle is trying to keep the bow up and lifted, but it's not enough. Some of that can be caused by the wrong prop, some by the hull. As otherwise I'd opine (thru cyberspace review anyway ... ) that your mounting height looks good.

HOOKS & ROCKERS (from iboats) - When viewed from underneath the boat, looking up at the bottom, a hook is a concave deformation of the bottom along the keel line. If the deformation is convex in shape then it is called a rocker. If you put a straight edge of about 6' in length along the keel line, from the transom going forward, you will easily see if you have a hook or a rocker in your hull.

A hook will cause the bow to dig in the water when you're on plane until you add excessive trim - at which time the hull usually starts porpoising. A rocker will porpoise most of the time at any trim setting and the boat will handle very weirdly. Sounds like your situation :?: ? Both hooks and rockers are usually spread over a 2-4' region just in front of the transom. They should not be confused with shapes/transitions that the hull designer may have added as a design feature.

The photo attached was from a recent post where I showed someone else how to confirm that they had a 'hook' in their hull.

DH Note - I believe that either could be created onto a tin hull by an improperly setup trailer (bunks, rollers and/or their positions (fore/aft or side-to-side) with heavy road use, damage, too heavy hull loading, or impact or just age and settling on an old aluminum boat ...
 

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IMG_1163.JPGIMG_1159.JPGIMG_1160.JPG I am surprised I didn't see this one myself. I had looked under the bottom a few times but the bunks blocked the view of the very middle. That blue thing is a steel post I used for a straight edge. Looks like somebody once found one of the St Lawrance River's legendary rocks. It doesn't look too bad though, the keel seems straight itself. Not like anyone needed a straight edge to see it though #-o View attachment 2 Funny I didn't see it when I was gutting the foam but being right under the livewell it could have been under one of the cross members. I guess sometimes a guy can miss something he isn't really looking for.
hopefully I can easily enough get at it from the inside and bump it out with a BHF and dolly. The other pic shows a couple small spots where the hull looks to have pulled down a tad from the sub keel or whatever those lateral slats are called. They don't look to bad to me though, just the big guy forward #-o Oh I just remembered, the boat has a Doel fin on it too (another sign). I took it off and it was far worse to control. Of course I put all this off to the wet foam at the time. [-X The last pic is the prop. Pitchy little critter seems to me and one more fin than I like too. The boat had a doel fin on it too. I took it off and it handled horribly.
 

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I was hoping to get some sort of opinion on this dent picture (poor as it it). FWIW it is about the size of an outstretched hand. the middle is about 1/2" deep and radiates out from there. Of course it had to land on a brace which probably kept it from becoming a lot worse than it is though it did all but completely miss the keel.
So do you boat bodywork guys think this is likely the issue?????? I definitely wont be covering anything up after I pound it out then test run it. Also what about that 4 blade prop? I'm not swapping anything else out this year but overall wouldn't that be far better if I went back to a 3 blade? For all I know the guy was pulling water skiers and I sure wont.
 
DENT - I'd be inclined to leave it as is, believing you could cause more structural deformation/damage by trying to fix it.

PROP - The issue isn't 3 or 4 blades, but rather ... is either the 'right pitch' for that motor as setup? Go to the motors forum and use that prop pitch calculator by Turning Point Props that I've posted. That calculator is SPOT ON!

Further, I just bought one of the new 4-blade aluminum performance props brought out this year by Turning Point and it is PHENOMENAL! Less than $100 too, for my 60hp Johnson. They are being aggressively marketed as "SS performance at an aluminum prop price". Looks like what I'd call a 'raker' or 'chopper' prop, if you look at the picture uploaded. I'm getting < 5% slip as currently setup, where my OB vent plate rides just above the surface of the water whilst on plane.

FWIW I've used wheels from most makers, OMC, Merc, Yam, PowerTech including up to $600 custom props from https://www.propgods.com for my Suzi 250hp OBs on my offshore boats and I will say that for smaller OBs ... I've had nothing but spectacular success with props on my small motors (8hp, 18hp, 40hp and now 60hp) by using the T-Point props.
 

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