Hello

I was wondering if I could run a few questions about pumps and pump applications. First of all I have two pumps, a HCM 75 and a HCM 100.
I have a well point 37 feet deep with a 1 1/2 rigid galinized pipe. The actual water level is about 18 feet from the top of the ground.
From the top of the ground I reduced the pipe to 1 inch and used a check valve (to insure that the prime stayed in the pipe) then ran the pipe horizontal 28 feet. I did this to hide the pump and tank next to the house. I only use this pump for my sprinler system and have been for 4 years. Now for problem number 1.

Problem number 1
My HCM 75 was left out this winter and the case cracked. So i am looking for a place to purchase a myers hcm 75 case.

Problem number 2
My HCM 75 (when it was operational) would run three sprinkler heads at about 34 PSI and would produce about 8 GPM. Which is ok with me because it is free water, i just have a whole lot of zones on my rain bird system. Anyway, when i replaced my HCM 75 ( Because of the cracked case) and installed the HCM 100 my zones that have three heads no longer produce the spray pattern they did with the HCM 75.
In other words the Hcm 100 does not produce the same amount of flow and psi as the smaller HCM 75. So what i am asking is what could be wrong. The venture seems ok but i have not broken it all the way down to see the impellers.
Is there a rebuild kit for these pumps?
Are there certain thngs to look for?
Is there a better pump for my application?

Thanks

diagram below (best i could do)
check valve with 90 elbow)
Pump-----------------------------
*******25 feet*************|
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****water level 18***********|
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*37 elbow to well point********|
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*1 1/2 with 1 1/4 bell*********#
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*3 foot well point@1 1/4)******#
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