# Prop blow out after adding jack plate to 1648 mod v Jon boat



## K3anderson (Jan 23, 2013)

Cup the SH$% out of your prop.


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## TXJM (Aug 14, 2020)

looks like you might want an sra3 or sra4 instead of the tlr3 prop. The sra’s will hang a lot better when running elevated. 
Chip


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## Captainp (Nov 27, 2016)

Get some cup put on the prop. I've got a gladesmen with the same motor with a 13 pitch prop and I had the same problem after I put a hydraulic jp on it. I put a bunch of cup on the prop and can now run it on a plane jacked all the way up.


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## Garage Specialty! (Jun 24, 2021)

Spoke with Ken at prop gods and will probably get a sra4 in 10x11. In the meantime will also add more cup to the existing prop since there’s a pretty good shop nearby that can do that while I wait on site and will have a nice spare just in case. Will come back with results. Thanks!!


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## eberin (Jul 11, 2018)

Interested in your results, I have a 1648 G3

Was the motor install easy on the bobs jack plate?
I have a Yamaha 25 4 stroke too (98)

I just read there is interface the bottom bolts using a micro atlas, even with the clamp on bracket, there is another thread on this site

I’m def more instered in the bobs jack plate but wondering if float pods would be needed with the extra weight 

my F25 came with a 9 7/8 X 10.5 prop

Pics are below for my comparison


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## Garage Specialty! (Jun 24, 2021)

eberin said:


> Interested in your results, I have a 1648 G3
> 
> Was the motor install easy on the bobs jack plate?
> I have a Yamaha 25 4 stroke too (98)
> ...


Stock mine was a similar height with short shaft f25.

install was straight forward. The previous owner did strengthen the transom area where the motor mounts with 1/4” aluminum plate but I don’t think that’s necessary.

After mocking everything up I drilled the transom for the BIA mounting pattern of the bob’s and bolted it on after running beads of 4200. After I set height for the f25 I drilled the bob’s plate for the yamahas bolt holes since these are not wide enough for the BIA standard (and I wanted the motor higher) and used a 2x4 to build enough thickness for the clamp on mount. Will replace the 2x4 with a piece of 1.5” starboard later. I’ll take some pics and send them to you.

I run a yeti 45 with 20pounds of ice up front with I pilot TM and a group 27 battery and don’t plan on adding pods. If anything I’ll just relocate the house battery (group 24 size) from the stern to offset the jack plate and hydraulic pump weight but didn’t have any issues with weight or balance when I took the boat out with 2 anglers on board it performed how it usually does in calm to slight chop. Only went as shallow as 10-12” last trip but had no problem floating over. Will try and get to 6” or less this weekend.


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## Garage Specialty! (Jun 24, 2021)

Quick update. Went with a 10x10 sra4 prop. 4900-5000 rpm at 0” height and 5600-5700 rpm 3” raised. Finally able to see the cav plate while on plane. Need to play with trim settings and balance the boat how I would normally with only 2 people.

achieved 24mph with with 2 anglers and an additional 120 pound teenager on board.


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## TXJM (Aug 14, 2020)

Garage Specialty! said:


> View attachment 189724
> 
> 
> View attachment 189726
> ...


Nice. Glad you are getting it dialed in.


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## Garage Specialty! (Jun 24, 2021)

Me too.








With my normal load of 2 anglers. About 2.5-2.75” up on the JP @5400-5500rpm (if I can remember right) I am averaging 25mph. Saw a max of 28.2mph. Using a dual xgps160 unit.


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## TXJM (Aug 14, 2020)

Garage Specialty! said:


> Me too.
> View attachment 190531
> 
> With my normal load of 2 anglers. About 2.5-2.75” up on the JP @5400-5500rpm (if I can remember right) I am averaging 25mph. Saw a max of 28.2mph. Using a dual xgps160 unit.



Sounds like that you have about the right pitch. What happens as you raise it from there, other than the rpm goes up?


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## Garage Specialty! (Jun 24, 2021)

TXJM said:


> Sounds like that you have about the right pitch. What happens as you raise it from there, other than the rpm goes up?


rpm up, speed down. 
At 6” up I have forward progression/bite up until about 3000-3500 rpm. At this point I’m wondering if I’m limited because of the flat bottom or if a pressure/cav plate would help keep water around the prop.


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## TXJM (Aug 14, 2020)

Garage Specialty! said:


> rpm up, speed down.
> At 6” up I have forward progression/bite up until about 3000-3500 rpm. At this point I’m wondering if I’m limited because of the flat bottom or if a pressure/cav plate would help keep water around the prop.


I vote for a cav plate. I have a transport on my 30. I used to have a permatrim on a 20. The permatrim made a huge difference and was cheap. I have never run the 30 without one so I can’t comment on it but they are highly recommended. 
Chip


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## Garage Specialty! (Jun 24, 2021)

TXJM said:


> I vote for a cav plate. I have a transport on my 30. I used to have a permatrim on a 20. The permatrim made a huge difference and was cheap. I have never run the 30 without one so I can’t comment on it but they are highly recommended.
> Chip


went ahead and ordered the permatrim, mainly on costs. Definitely not going to have All the benefits of a shaw or a Tran but hoping for some improvement. Need to stop over investing in this jon so I can switch over to a nicer skiff next year or so without the hull slap that can handle mild chop in the bay more comfortably (not often, but would be cool to have the capability)


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## Garage Specialty! (Jun 24, 2021)

Was able to get this guy for a decent price.


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## Garage Specialty! (Jun 24, 2021)

probably going to go above the cav plate Just in case something gets wedged between the prop and the plate it won’t crack the fiberglass.


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## Germs (Nov 19, 2011)

Another perspective, currently running a G3 1652 with a 50 yamI, atlas jack plate for 3 year,
tried various prop and found the power tec SWC4R11PYS50 gives me the best hole shot
and little to no blow out, I lose 1-1/2 miles per hour over a stand 4 or 4 blade.


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## scottharris (Jun 6, 2013)

Garage Specialty! said:


> Was able to get this guy for a decent price.
> View attachment 191396


Question…did you find it used?? Or buy it new?? If so, what was the new price?? I’m currently considering getting one!! Thanks in advance!


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## devrep (Feb 22, 2009)

SWC is a badass prop.


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## Germs (Nov 19, 2011)

scottharris said:


> Question…did you find it used?? Or buy it new?? If so, what was the new price?? I’m currently considering getting one!! Thanks in advance!


Bought it new, it’s been a couple years, somewhere around 400.


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## Garage Specialty! (Jun 24, 2021)

scottharris said:


> Question…did you find it used?? Or buy it new?? If so, what was the new price?? I’m currently considering getting one!! Thanks in advance!


Luckily I got it used (uncut) from @Inshore_Inc. for an awesome price.

might wanna give trans port a call
TRAN'S MARINE MARINE SERVICES
361-972-6629


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## scottharris (Jun 6, 2013)

Garage Specialty! said:


> Luckily I got it used (uncut) from @Inshore_Inc. for an awesome price.
> 
> might wanna give trans port a call
> TRAN'S MARINE MARINE SERVICES
> 361-972-6629


I know…you beat me to that one!! I messaged him and he said it was gone! Can’t wait to hear how it performs!! Merry Christmas!


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## Inshore_Inc. (Sep 16, 2014)

Garage Specialty! said:


> Luckily I got it used (uncut) from @Inshore_Inc. for an awesome price.
> 
> might wanna give trans port a call
> TRAN'S MARINE MARINE SERVICES
> 361-972-6629


Glad to be able to play a part in this project. Lookin good bud. Post some final install pics and results


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## Garage Specialty! (Jun 24, 2021)

Screenshot 








Where I’m thinking the boats water line is on plane compared to screenshot above. 


Minimal time on the water. But overall, great results!!! Tested with 2 anglers. 

Few observations:
-Holds tight in turns at all JP heights (used to blow out and/or slide on tight turns when jacked up 3”)
-Runs and gets on plane at full 6” height, just can’t go WOT cause it’ll go slightly over 6000rpm.
[email protected]” rpm 5900-6000rpm.
-Able to trim motor (without cav plate it would lose bite at any trim setting except fully in) 
-Gets up on plane super quick
-I think sweet spot will be between 4-5” and trim fully in but I’ll have to test more 
-Top speed 24.7mph on xgps160, and cruise was around 22mph, but on less than ideal conditions, will have to test more.


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## Steve_Mevers (Feb 8, 2013)

4 blade prop will make a world of difference in bite,


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## Inshore_Inc. (Sep 16, 2014)

Garage Specialty! said:


> View attachment 191609
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> View attachment 191606
> 
> ...


Dude! Thats great, doing exactly what it should do. Glad your seeing some results.


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## Smackdaddy53 (Dec 31, 2012)

Steve_Mevers said:


> 4 blade prop will make a world of difference in bite,


In many cases a three blade with a ton of cup is as good or better but it needs to be the right three blade.


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