Speed and RPM issue

DHChapGuy

New member
I just purchased a 2018 287SSX Chap with the 8.2 Mercruiser (380HP) engine. Having issues with top speed and RPMs. This boat is supposed to go 48-50 mph and reach 4,800-5,000 rpms per several reviews. I cant get it above 36 mph or 4,000 rpms. Right now it does have a pretty dirty bottom in the rear because it was kept in the water. Previous owner pulled it out monthly and cleaned bottom but could not get to area under trailer. Plugs were changed about a year ago. It seems to run well, just slow. :) Would the dirty bottom impact this much. I will get it cleaned up soon because I will keep it at very clean Dale Hollow lake on a lift. Looking for ideas from this group. Thanks.
 

Phillbo

Active member
May need a different prop. You want to achieve WOT as speced. These engines do not like to be lugged....
 

DHChapGuy

New member
I will check into that after i get the junk off bottom if that doesnt help. It supposedly still has OEM prop. Thanks
 

markt111

New member
Are you an experienced boater? Are you trimming the boat properly? Prop pitch, condition could also be a factor, verify they are proper and the engine in good tune along with cleaning the bottom then report back... lots of questions that need answering...

here's some reference of what the baaot should run:

 

DHChapGuy

New member
Yes. Been boating for 20+ years and definitely trimmed properly. I still need to have prop checked and get the bottom cleaned. Engine was tuned in Aug 2021 per invoice seller shared with me. but still planning on having my guy check as well.

I have seen that video as well and that's the expectation.

Thanks.
 
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