F-28 Performance

shawzy44 · Post by **shawzy44** » Mon Aug 23, 2010 2:39 pm

I've been playing with the tabs for a while now. I have them reacting MUCH quicker and can get her to plane fairly quickly.

I get about 12kt @2700 RPM and WOT 23kn @4400 RPM full fuel and water.

herpleasure · Post by **herpleasure** » Mon Sep 12, 2011 10:17 pm

Dreamer,
I am interested in your props. I have a 79 f28 that is doing 2800PRM (which is all it will do) and 12 MPH. The motors run good. You seem to have found the key

prowlersfish · Post by **prowlersfish** » Mon Sep 12, 2011 11:19 pm

herpleasure wrote:Dreamer,
I am interested in your props. I have a 79 f28 that is doing 2800PRM (which is all it will do) and 12 MPH. The motors run good. You seem to have found the key

Sounds like you have a fouled bottom and or running gear

prowlersfish · Post by **prowlersfish** » Mon Sep 12, 2011 11:20 pm

herpleasure wrote:Dreamer,
I am interested in your props. I have a 79 f28 that is doing 2800PRM (which is all it will do) and 12 MPH. The motors run good. You seem to have found the key

Sounds like you have a fouled bottom and or running gear

prowlersfish · Post by **prowlersfish** » Mon Sep 12, 2011 11:20 pm

herpleasure wrote:Dreamer,
I am interested in your props. I have a 79 f28 that is doing 2800PRM (which is all it will do) and 12 MPH. The motors run good. You seem to have found the key

Sounds like you have a fouled bottom and or running gear

Dreamer · Post by **Dreamer** » Mon Sep 12, 2011 11:27 pm

The two things that made the biggest in Dreamer, was rebuilding the engines with a very mild cam. New carburetors, and stripping the bottom and using VC-17. I know that's more than two. The props I believe are at the factory pitch.

willietrojan · Post by **willietrojan** » Tue Sep 13, 2011 9:01 am

I guessing your engines are the original, how many hours? I would suggest getting a compression test, this sound like the engines are worn out

prowlersfish · Post by **prowlersfish** » Tue Sep 13, 2011 1:06 pm

2800 rpm should be faster then 12 MPH . 2800 rpm is 2800 worn out or not ,

Willie have you found a new boat yet ?

Capt. Z · Post by **Capt. Z** » Tue Sep 13, 2011 2:04 pm

prowlersfish wrote:2800 rpm should be faster then 12 MPH . 2800 rpm is 2800 worn out or not ,

Willie have you found a new boat yet ?

I have to agree with Paul. 2800rpm is where I cruise at with my F28. 2800rpm is right at 22mph, WOT is 4100 rpm at 34mph. The 318s are no where near fresh either, 1600hrs.

With a little more info maybe we can help you get to the "bottom" of your problem!

foofer b · Post by **foofer b** » Tue Sep 13, 2011 8:01 pm

prowlersfish wrote:It is not a engine problem !!!!! your only gets 13-14 knots at 3200 ? well no matter what you do to those engine you still only going to get 13-14 knots at 3200. you could tune them up put a blower on it and get 700 hp out of them But your still only going to get 13-14 knots at 3200 rpm .

unless the engine is missing don't waste you time with a compression check . even if you had 2 dead clyders it will not change your speed at a given rpm. (yes of course it would efect top rpm. )

look else where

Once again Prowlerfish is spot on. Rpm is Rpm no m,atter what the HP.

alexander38 · Post by **alexander38** » Wed Sep 14, 2011 4:10 am

captainmaniac wrote:If you have to give your mechanic a list of what to check to diagnose your problems, maybe you found your problem - you need a new mechanic! If he can't tell *you* what needs to be checked, don't let him touch them.

omg ! we agree

I've a question, will it rev up out of gear ? lack of gas at higher rpm it'll back fire and or fall off all together. And whats the bottom look like a fouled bottom or a painted one that looks like the moon will kill rpm/speed. also have you checked alignment ?
And engine hrs. don't kill engines lack of maintenance kills them, my 454's have over 1700 on them and push me up 25 knots with a smooth bottom.

shawzy44 · Post by **shawzy44** » Wed Sep 14, 2011 1:55 pm

Alexander38,

What do you mean by alignment? Alignment of what exactly?

prowlersfish · Post by **prowlersfish** » Wed Sep 14, 2011 6:48 pm

Engine alignment

alexander38 · Post by **alexander38** » Thu Sep 15, 2011 5:16 am

prowlersfish wrote:Engine alignment

to shafts and cutlass bearings

prowlersfish · Post by **prowlersfish** » Thu Sep 15, 2011 6:55 am

alexander38 wrote:
prowlersfish wrote:Engine alignment
to shafts and cutlass bearings

Not exactly , you aligne the engine to the shaft and the shaft to the cutlass , its really 2 different things to do , but one effects the other . as a general rule , cutlass/strut alignment will effect cutlass wear , engine to shaft can cause vibration and possible shaft failure .

To cause a power loss the alignment would have to be so far off the shaft would be in a bad bind . if you can rotate the shaft then I don't think this is the issue .