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geno1979
05-26-2002, 05:44 PM
I just bought an 89 Cheetah 210ES it is my first boat. It has the 5.0 with a 1.5:1 ratio and a 19P it only runs at 40-41 mph at 4800 is this normal. Everyone says this was supposed to be a fast boat. Also it has no trim tabs and a 2 barrel carb is it worth adding trim tabs or a four barrel?

24ROD
05-26-2002, 08:09 PM
geno what type of a hull is it? Is it a vee, or a tunnel? But on the other hand does not sound like it's got a bunch of power.

geno1979
05-26-2002, 10:30 PM
Its a V it seems like it runs strong. But do you think the trim tabs or 4 barrel are worth it?

bigq
05-28-2002, 08:34 AM
Geno,
I would think it should be more in the 55-60 tops with that motor.Not a lot of power ,but 45 is slow. Are you just reading the speedo because it is not that acurate. Tabs wont help with the speed.If you change the carb to a 4 venturi then you need to change the manifold also, it would help with the top end some.

XTRM22
05-28-2002, 09:05 AM
Hey Geno1979, I'm sitting here avoiding work and saw your post and ran the calcs real quick. With a 19" prop turning 4800 rpms, you are running about 52mph with 9-10% slip (theoretically) and with the 5.0 motor on a 21ft vee, you are about right on track. An intake and Carb would give you some improvement, but I'd play with some props first! We had a land and sea torque shift prop on a 19' vee with v-6 with manifold and 4 barrel. Pulled hard out of the hole and would just touch 50-55. Good Luck
Chuck

XTRM22
05-28-2002, 09:09 AM
OOps, almost forgot, if you are pretty sure your speedo is on, get another prop cause that one isn't working for you. :-)
Chuck

geno1979
05-28-2002, 12:22 PM
Im sure the speedo is close I had my friend with his jet ski clock me. I put a 21P on and it doesn’t get out of the hole at all and the rpms won't rise past 4000. Maybe the engine is tired.

XTRM22
05-28-2002, 04:45 PM
Dude if you are turning that 19" to 4800, and only going 41-42 you need to try a different 19". My 19' Galaxie with 350 mag would turn a 4 blade 20" to 4700 but couldn't turn a 23" 3 blade past 4100 so I understand your dilema. That 5.0 might be tired but the prop numbers still don't work with the speed unless you have like 20%+ loss to slip. That's either prop or hull and I never heard of a Cheetah with that low efficency. I'm no expert, but I'd play with another couple props before I went to the engine.
my .02
Chuck

Charley
05-28-2002, 08:47 PM
listen closely to Chuck grasshopper Geno....he is masta of squeezing miles per howa from small boat shaped like V
[This message has been edited by Charley (edited May 28, 2002).]

geno1979
05-29-2002, 07:45 AM
So how do you go about trying to find the right prop is there a method? What should i try doing?