20 CC WOT numbers

[jwclbi]

Hello, I have 1973 20CC with a 1998 225 EFI Merc. Put the boat in yesterday after installing a new garmin gps. The problem is, with 4 adults and 40 gallons of fuel i was only getting 48-49 miles an hour. The question i have is anyone running same boat with similar power and what numbers are you getting and full throttle? compression test today. thanks

[DonV]

"i was only getting 48-49 miles an hour"

Only??? With four people?

[jwclbi]

yeah i know that sounds bad but but 10-12 years ago she ran upper 60's with me and one guy on board with a handheld gps. I never had gps on the boat until I installed one this spring. Compression test today showed why, all 6 cylinders were low 90's.

[Reelsknotty]

I had an '86 20' with a 225 Optimax and it was a 54mph boat. I saw 56 a few times, but never more. Based on that, id say you're in line.

[pelican]

Originally Posted by jwclbi

yeah i know that sounds bad but but 10-12 years ago she ran upper 60's with me and one guy on board with a handheld gps. I never had gps on the boat until I installed one this spring. Compression test today showed why, all 6 cylinders were low 90's.

confused...


all cylinder reading the same number ?

[Bigshrimpin]

Check the cavitation plate make sure it's 1.5" above the bottom v. For what it's worth, I just put on a Merc 225 3.0L carb motor on my 23 WOT bounced b/w 49.3mph and 48.6.