Motor height ?

[wayne72472]

Was looking at the motor and it looks like it could be low what do you guys think? should I raise it up it’s a 2001 Special edition tournament 18 foot with a 90 horse mercury I am getting about 37 miles an hour out of it now turning 5000 rpms full of tackle and 3 batterys and i added more deck space for the tackle running the aluminum three blade prop 21 pitch 53362AA4-EDA6-433A-BC02-65E50980EB43.jpegD451691F-1D3C-4239-890C-589096F762EC.jpeg

[Extremeboating]

You could probably benefit from raising up the motor one hole. 5000 RPM sounds a bit low to be honest. You may want to pull the RPM specs for your Merc motor and see where they are at and ensure that you are fully trimming your motor out when at plane. Regardless, that RPM most likely needs to come up.

[LT4247]

I have the same boat and motor. I have the motor mounted in the 3rd hole (2up from where you are) and it runs/handles great. Actually the idiots at the dealer mounted the motor in the 4th hole when it was new and i ran it there for a while (factory says mount in 2nd hole so they did FROM THE BOTTOM!). It would blow out in turns some,,lol. If you ask around most folks will say run it in 3rd hole for best performance but 2nd hole is ok.
I get 43 mph GPS @ 5500 RPM running a SS 21” 3 blade prop. I fish rivers with rocks/shoals a lot so i also will run a Pirana 4 blade composite 22” some. I still get about 41 mph @ 5400 rpm and the bow lift and handling is excellent on the 4 blade. Oh, the Pirana is light weight so there is not prop clutch rattle. At 5000 rpm your motor is struggling a little. The range on the 2 stroke 90 is 5000-5500 so 5500 is better. Your Mercury aluminum 21” should put you right at 5500 rpm (does on mine). Raise the motor and see what you got.

[wayne72472]

thanks for the info guys

[bassfisher444]

2nd hole from the top if you keep the aluminum prop, 3rd hole if you go stainless.

[wayne72472]

up date
i pulled the motor off and put it in the second hole and i really cant tell that it helped. wondering if i need to go to the third hole and try there ?