set-up for my 21 spectra checkmate

[themdshrk69]

I am currently running a 21' checkmate spectra with a v-8 johnson supoosedly modded to 425hp mounted to a land & sea hydraulic jack plate with about 4.5" of set back turning a 26p ballistic prop. So far we have run 81.4 mph at sea level on gps :) turning 6300 rpm. Now here is the question we wanna go faster:eek: :cool:.have tried diferent props a 28 and a 26 raker both slower than the ballistic. I also have a 4 blade to try just need different thrust washer/spacers. I can run the trim to the max and we run the jackplate all the way up and still have 16lbs of water pressure so I think there is room for improvment:cool: maybe more height or setback:confused: or both. have looked at Bobs spacers 2" will they work with my current set up (would have 6.5" setback) and can I raise the motor on the jackplate with them, or should I just bite the bullet and buy a new jackplate:confused:. and after all this info what should my set back be and my propshaft hieght be for this boat and motor combo and any thoughts on running the 4 blade,am thinking of having the ballistic worked or is this a waste of time. Thanks for your time all sugestions are appreciated,See ya at the Rondack Romp:D :D :D

[Fasttoys]

I have a feeling your on the right track. I run 5 inches of set back on my rig and it seems like the longer heavier rigs that perform well always have somewhere around 10" of setback. I'm not sure what height you run your motor at right now, but if you don't use the lowest part of the range of your jack plate and you still have water pressure when your all the way up, why not remount it to go a little higher? That said, 81 is pretty fast in your style Checkmate, but we always want a little more don't we? :cool:

See you at the Romp....:D

[Fasttoys]

Let's try and help Mudshark out here. Someone out there must have the same or very similar Checkmate and knows what the prop height and set back should be for optimum performance on this rig. I'm by know means an expert and I've never owned a boat similar to this but I'll take the first stab at it.

10" of set back and the propshaft 1 1/2"below the pad or lowest point on the transom.

Let's hear it from someone with previous experience on this or a similar rig!........and feel free to educate me if I'm way off base. ;)

Also.....did any of you guys ever see a 21 ft Checkmate hit 90? I think Mudshark will soon have the fastest one around. :cool: :D

[illMATTic]

i know those spectras are pretty heavy. i bet even with that V8 on the back you could use more setback. I would like to see a 12" or bigger box if the transom is solid. shoot, think about the guys with superboats; they run 10"+ with a 4 stroke and weigh way less.

[HONDAM]

I have a 21' checkmate pulsare with a Honda 225. Im running 5.5' of setback on a cmc powerlift. The biggest performance upgrade that i have done was sending my gearcase to Titus at Custom Marine and Welding. He put a low water pickup in the nosecone on mine and did something with thr cavitaion plate. Also did something with the paint that supposed to give me a couple more. I have no idea what your running right now but maybe some modification to the gearcase will help. My boats probably alittle lighter then yours, dont know much about the spectras but with almost twice as much hp, does seem like you should be moving better then that.
http://i118.photobucket.com/albums/o103/hondam/Checkmate/Pulsare/100_0636.jpg

[83PREDICTOR]

I am not sure if you can take that Ballistic much highier. I ran one on my 16.5ft Checkmate when it had a 115 on it. It was the fastest prop I tried but I had to run it below 3 inches. Any highier it would cavitate with any trim or turn of the wheel.

[themdshrk69]

i know those spectras are pretty heavy. i bet even with that V8 on the back you could use more setback. I would like to see a 12" or bigger box if the transom is solid. shoot, think about the guys with superboats; they run 10"+ with a 4 stroke and weigh way less.transom is solid but we get a little flex at the top corners of the motorwell just behind the seat in rough chop, so we are going to build some rods to run from a plate on the transom down to some plates on the stringers like on superbenders boat. checked his out at the romp last year sweet set up:D :D also my lower unit has a nosecone on it. where can I get a box or should i just buy a new jack plate 12":confused: Anyway thanks for the tips keep them coming, I ran the same post on checkmates .com and only got 1 reply. Also I called checkmate and found out Kunkels in Ohio sold the boat new so I am also going to call them for some insight, they have set up some really fast starflights:eek: :eek: they seem like good people.

[themdshrk69]

I have a feeling your on the right track. I run 5 inches of set back on my rig and it seems like the longer heavier rigs that perform well always have somewhere around 10" of setback. I'm not sure what height you run your motor at right now, but if you don't use the lowest part of the range of your jack plate and you still have water pressure when your all the way up, why not remount it to go a little higher? That said, 81 is pretty fast in your style Checkmate, but we always want a little more don't we? :cool:

See you at the Romp....:DUnfortunatly my plate is mounted as high on the transom as possible right now and motor to jackplate is as high as posible with this style land & sea plate:(