Ficht question

[THEFERMANATOR]

Originally Posted by evilgli

with the 15X17, 3/4 of a tank of fuel, 3 guys on the boat, tackle, ice, no tabs, boat will do 43MPH and engine will turn 6000 RPM WOT.. i will give it to the 200 ocean runner, she likes to scream and suck the fuel..haha

You may want to have your prop and tach checked. Your numbers come out to 17% prop slip which is HUGE for WOT. 8-12% is the normal range, but much more than 10% is pushing it. Something definately isn't right with those numbers. I get roughly 2-3% prop slip with my APOLLO prop which gets me EXCELLENT bite and economy. You may be able to improve your economy noticeably just by re-propping and checking your set-up.

Next time your out check your engine height like in this post and see where your plate is in the water column underway. If it is too high that will cause your excess prop slip.
http://www.propgods.com/forum/default.aspx?g=posts&t=97

I would suggest you try and find one of these for a prop. A 15 pitch in a MIRAGE PLUS would be just about ideal for your app and speed. You might also want to have your tach checked for accuracy to make sure it's reading right.
http://cgi.ebay.com/ebaymotors/New-M...item2ea8b29e0b

[evilgli]

Originally Posted by THEFERMANATOR

You may want to have your prop and tach checked. Your numbers come out to 17% prop slip which is HUGE for WOT. 8-12% is the normal range, but much more than 10% is pushing it. Something definately isn't right with those numbers. I get roughly 2-3% prop slip with my APOLLO prop which gets me EXCELLENT bite and economy. You may be able to improve your economy noticeably just by re-propping and checking your set-up.

Next time your out check your engine height like in this post and see where your plate is in the water column underway. If it is too high that will cause your excess prop slip.
http://www.propgods.com/forum/default.aspx?g=posts&t=97

I would suggest you try and find one of these for a prop. A 15 pitch in a MIRAGE PLUS would be just about ideal for your app and speed. You might also want to have your tach checked for accuracy to make sure it's reading right.
http://cgi.ebay.com/ebaymotors/New-M...item2ea8b29e0b

just had the prop redone about 2 months ago.. not i say i hit 6000 RPM at WOT..that is with the engine trimmed WAY up.. say if i leave the engine trimmed in the middle of the gauge, the engine will only run about 5600-5700 RPM at WOT.. when the engine was in the shop about a month or so ago when i had stuck open thermostats kicking my *** (i know dumb), the techs said my tach was working fine. don't know if this makes a difference.. i will check the plate next time i'm out.

[evilgli]

will keep my eyes open for a prop.. would like to get my hands on one before i buy and see what it does

[THEFERMANATOR]

5600 RPM's at 43 brings your slip back down to 11-12% which is better, but still high.

[evilgli]

that lower is a 1.83 gear ratio correct?

[THEFERMANATOR]

1.86:1 iirc

[evilgli]

well i finally got the boat out today and was able to see how my newly installed fuel flow sensor worked.. had me, wife and the 2 kids on the boat. 50 gallons of fuel in the boat and almost calm flat river conditions

the ol 200 johnson ocean pro was using 2 GPH at idle in neutral

cruising at 4000RPM produced 28.6 MPH using 11.4 GPH

cruising at 4500RPM produced 33.7 MPH using 14.2 GPH

trolling at 1800RPM produced 6.51 MPH using 3.4 GPH

and drumroll....wideopen trimmed up at 5800RPM produced 44.4 MPH using 24.5 GPH (OUCH)

and i also checked the cavitation plate running wideopen and the engine trimmed in the middle and i could see it just below the water line, so i think the engine is mounted properly..

whatca think ferm??