I have a 42 fountain 2006 with staggered 525 with 32p 4 blade bravo she will hit 80 at 5200 rpm with trim at 5 on the gage. no problems with overheating. Are you getting good water pressure ?

what about the 38 !!!???

You're new to high performance boats and have a Fountain with twin 525's? Take Tres Martin's course!

A 38 Lightning with 525's should come with 32 pitch 4 blade Bravo 1's. The boat should run around 90 at 5250 rpm.

Sounds to me like you may need transom mount raw water pick ups but i would be surprised if it did not have them already.. The 5 is a lot of prop for that set up i would think a 28 or 30 B1 but thats just a guess on my part, and yes the 28 will bring up the rpm

How many hrs are on he motors?? The first thing you lose is RPM when the motor is getting weak. Might what to check that.

Props are too big, especially with the extreme high air temps you have. High ambient temps cause a loss of HP.
If you switched to 27" Maximus props or 30" Bravo 4 blades you would see about 5100rpms.

i can see it already,,his next comment is going to be that his props blow out after switching to 28 bravos....lol

+1

120 degree ambient temp will hurt power a lot, surely it should call for at least one pitch less than normal

Thanx Keytime looks good!!