Prop Slip?

[jrokk27]

How many RPMs should I expect to see with my motor and prop setup? I have yet to measure pad.
I am running a Tempest 27P. Thinking about getting the prop reworked because I think it is slipping too much and it has a few nicks and dings and a little hitch in it when I spin it by hand. I currently can't find over 5200 RPMs.

[BILLY]

What's the GPS speed?

[jrokk27]

56-64 depending.

[James.Harner]

You should get 5800-6000 out of the 27 tempest in good condition. Have it balanced and blueprinted by Mark's Propeller. Nicked up props can kill performance. The 225 H.O. is a beast for a 225. Your boat should get up to 72-73 lightly loaded without a problem. I have seen 75 in Florida very light, ran 73 las weekend with a 27 Fury. Your motor may be too low, keep an eye on the water pressure, but see if coming up on the plate helps some. Let me know if i can help. Thanks, James

[jrokk27]

Can you explain or tell me what to look for when it comes to water pressure? Should the pressure be higher or lower compared to motor height?

[James.Harner]

As you raise the motor on the jackplate, make sure the water pressure doesn't drop. I think your prop is most of the problem.do you know what pad to prop shaft meaurement is? Also, you think your prop is slipping, shouldn't be a problem with a 27p unless motor is jack up and it would surface some in sharp turns. Try not to let that happen, rude lower units will not hold up long that way.

[jrokk27]

Not exactly, but I plan to read up on it and get outside and get some measurements soon.

[BILLY]

James, What prop you running?

[James.Harner]

I run 2 different props normally, a 4blade 26P Trophy on the Potomac in the rough stuff, and a 27P Tempest Plus the rest of the time. I tried Thundercat's 27P Fury and my boat really handled well with it. I think I could turn a 28P Tempest in winter, but would lose all my holeshot. Summertime tourny load, I would have to drop to a 26P Fury I would suppose.

[Lea]

Prop to pad directions are pinned up at the top of this forum...

[jrokk27]

what is your pad to prop measurement?

[Lea]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by jrokk27 &raquo;</td></tr><tr><td class="quote">what is your pad to prop measurement?

</td></tr></table>

He is off line but the best starting point for prop to pad is prop shaft 3.5" below pad.

In my case, I run 3.75 below. You wll have to test your individual rig...it varies.

[James.Harner]

3.25

[jrokk27]

I plan to have my prop rebalanced, but I have a question in regards to my throttle adjustment and RPMs. I have a 27P Tempest prop and I am not able to get more than 5200rpms with my hotfoot mashed to the floor board. The pics were taken with my hotfoot at WOT. This doesn't look like 90 degrees to me, more like 75 degrees or less. Depending on the conditions and load I get 56mph-64mph WOT.

Could I be missing this plastic hose/roller on the throttle linkage that I have been reading about in other post? If so, where exactly is it located?
I would like to make sure my throttle is working correctly before I start spending money on props.

Prop to Pad is 2 3/4".
I have a manual Slidemaster jackplate with 10" setback

[James.Harner]

You rpm's do not sound right at all. Not sure about the throttle bodies, I will pull my cowling tommorrow and check mine. You are running your prop higher than I could go on mine. Above 3" begin to ventilate and slip in turns too bad and loose water pressure. Is there a rooset tail above your cowling(it can be an indication of motor too high also). It could be a throttle/rpm issue. You need to be in the high 5000's to keep these motors from fouling plugs and having carbon build up issues. What elevation (above see level) are you running at?

[jrokk27]

Someone mentioned adjusting the stop on the back of my hotfoot, so I will try that. I am around 1500ft above sea level here in Wichita, KS. My rooster tail is usually about the height of my cowling. I am leaning on this being a throttle issue.

[James.Harner]

I've lost a couple hundred rpms from a banged up prop(minor dings actually), elevation seems to be ok, I loose about a 100 rpm per 1000 ft of elevation change+/-, so that shouldn't be an issue for you. You may be right about the throttle/hot foot. With the motor that high, you should be on the limiter or close to it.

[kris_tx]

The roller is on the top left right where the grease is. I not sure if it is the same as tha carb motors, but it looks like yours is there. It looks like your throttle blades aren't open all the way. I would disconnect the throttle cable and then check to see if it goes wide open without the cable, then adjust cable/ hotfoot to get wide open.

[jrokk27]

It goes wide open when I push the top lever by hand.

[ChampioNman]

Ok, If nothing has changed with your hot foot, then unhook your throttle cable from the linkage post. Move the linkage to verify the plates are opening when you move the linkage. Adjust the cable to fit the throttle post. Then re-check the plates.