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Finally got back working on my T750 OMC motor

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 PostPosted: May 9th, 2017, 4:28 pm   
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Here is where I am at now: Boat is for the new RED Critchfield at TOP GUN's
- I started with a very clean Evinrude short shaft..foam cast block.
- the power head has been rebuilt and race prep
- gear case has been checked and resealed...perfect now
- got a second gear case and installed those inners in a new SST 60 case..it is perfect
- got a NOS short shaft tuner and reworked it. I am happy with it.
- just finished welding steering arm plates to the motor base plate..No engine bolt arm break issues!
- working on 3 ram Pro 50 Yamaha trim....just about done
- lower engine cowl bolts to steering arm brackets so cylinder head can be easily removed.

During the winter I purchased 2 more power heads both 100 series motors.
On other sites they talk about all 3 of the blocks and some prefer one over the others.
So I now have all three, All original non race motors
My BIG 100....the block number is in very large type.... has manual direct fuel prime into the cylinders...
Cool idea....and looks factory.

LC, Thom and Jeremy, if you have any secrets to share on engine builds..I am listing.
TOASTER WILL BE AT GRAVENHURST need a driver.


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 PostPosted: May 9th, 2017, 4:59 pm   
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Sounds like your on track!! i don"t understand why the welded steering bars?
Ive been anxoius to see you get this running on the red boat!
Ill take the big 100 off your hands ! lol
I also have a direct prime block( manual prime it was on a tiller but small 100)
I need to find more internals to build it

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 PostPosted: May 10th, 2017, 3:00 am   
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tunnelv wrote:
i don"t understand why the welded steering bars?

I welded steering bar mounting plates to the motor base plate. The SST 60 steering bars bolt to the plates.
With the plates you do not need to remove the steering arms to remove the power head and you do not need those custom 2 cylinder steering arms that crack where the bolts go thru,


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 PostPosted: May 10th, 2017, 8:11 am   
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That's great to hear Don, like Jeremy said can't wait to see it on the critch.

We currently run a big 100, the other one we have is a 207 block. Tough for us to compare the blocks as the 207 block was pretty tired and has high leak down.

Nothing fancy for us on the engine build, we never touched the ports heights from what factory was, the exhaust port is below the max exhaust height, I did clean up the width of the exhaust port and took it to the max of the spec which gives all around better power. The tuner we run is the stock short shaft tuner which we shortened. We've cut head, run 155 lbs compression on 91.

Most of our time has been spent in set up (you've always preached this) we've tried every prop we can get our hands on at various heights some work better at certain heights versus others it just a matter of taking the time to test. Todd and Thom built us a great prop last year which was worth every penny.

Knowledge sharing by the guys like yourself, The Gun, Todd, Thom and Jeremy have helped us build a competitive boat

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 PostPosted: May 10th, 2017, 11:24 am   
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What did you guys use for pistons? I just used new stock replacement OMC ones in the 207 rebuild. I now notice the shirt on the pistons of my 1985 60 hp small 100 block motor had MUCH larger cut outs in the skirt compared to the 207 and big 100 pistons. I think? this would improve performance. Do the aftermarket pistons have the larger cut outs? They would be worth trying.
I believe the piston on the right is a wisco. One on left is OMC.
http://www.boatracingfacts.com/forums/a ... 1381818957

The cranks look I bit different as well, but I have not studied them yet.
My Big 100 motor has had a good life to date and shows little wear and no sleeve or crank damage. I will rebuild it next. I will use the larger cut out skirt pistons.

With my left over parts I going to build a motor OMC never build in Canada. A twin cylinder 60 hp, short shaft, tiller, electric start [only] with a nitro case and factory power trim. I think it would be a cool motor on a small 12 to 14 foot AUSSI style aluminum. I tried to buy that Aussi style aluminum boat I posted a while back, but lost out.


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 PostPosted: May 16th, 2017, 10:42 am   
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Hi Don,

Both pistons you pictured are OMC pistons. The Wiscoe's don't have the relief notch to install and remove the cir-clips or e-clips (as some say). Yes, the after market Wiscoe's do have the large windows, but the replacement OMC's do not.

Can anyone tell me what the difference is between the small 100 block & the large 100 block? We run the small, since we could not round up a large 100 block.

Sounds like your doing all the right stuff. A speced out large 100 block, good tuner, 155-160 psi head. Steering bars sound great. Sounds like something I want to drive. I'll lose 75 lbs.

Later,

Thom


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 PostPosted: June 14th, 2017, 12:43 pm   
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Seaway Marine post:

The PH's I am selling are complete stock SST-45's - the magic block number, in my opinion having run ten plus PH's on the dyno, is a myth. The best motor I have found is a 207 block. In fact two of the best three motors have than block number. I am NOT building "Special Race Motors" - once you get a complete SST-45 PH from me - you can take it to whomever you want to have it blueprinted etc...

Thanks,

Greg


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