prop venting , need help!!

[dh99]

I have a DF 115 suzuki on my Lund fisherman 1800 and my motor is venting quite a bit. I have tried it on the top hole and its now on the 3rd hole from the top and the cavitation plate is even with the bottom of the boat.

Its happens more often when I am accelerating and I try to trim or if I am not at WOT throttle. It also happens when the water gets rough.

I have 2 different aluminum suzuki props. A 14 x 19 that runs at 6100-6200 rpms at WOT and 14 x 23 that runs at 5300-5500 RPMS at WOT on the 3rd hole from the top.

Can anyone give me some advice on what to try next.

I think I am going to lower the motor 1 hole.

Should I try a stainless prop and if so does anybody have any recommendations

[propmann]

How fast are you going with those prop you have how?

[dh99]

How fast are you going with those prop you have how?


With the 14 x23 I get 40-42 mph

14 x19 around 37-38 mph

[fxnrxn]

Dropping the motor is an inexpensive check, (although a little time consuming). My 115 (Mercury), on a 1700 Fisherman is all the way down on the transom. I know the Suzi's are geared different, but a SS prop usually doesn't flex as much (as aluminum), and has more cupping to 'bite' better. Maybe you're a candidate for a 4 blade prop. How does it plane? Does it get the spray to the back of the boat? Start simple, (and inexpensive) and work your way up to hydrofoils, props, shims and the like. (If you move the motor down, don't forget liberal amouts of silicone to the mounting holes to avoid problems down the road. Good Luck. Mike

[middleton1]

A good stainless steel prop will allow you to raise the motor back up and will stay hooked up better then the aluminum.

[dh99]

I forgot to mention that i also have a 9.9 kicker on the back so the back end is heavy

With the 14x 23 its slow to get out on plane and the spray is about 2-3 feet from the back when its calm and trim as high as i can get it. If it gets rough I cant trim up high enough to up on plane as much as I would like.

what does the 4 blade allow me to do.

I will lower the motor but I think I will eventually buy a stainless prop.

Anybody have any suggestions for a SS prop on my suzuki. and how do know what pitch to get with ss props compared to alum. props.

Thanks

[TomP.]

To my thinking that 115 on the 1800 and 14 X 19 prop would never hit 6100 RPMS. You have a lot of slip someplace either prop, motor to high, or over trimming. Is the speed GPS? Just because you have a lot of trim dosen`t mean that is where it runs the fastest or best.

When running rough water I don`t want to be trimmed very high I want the bow to cut the waves and not pound into them.

If it`s cavitating in rough water trimmed to high and aluminum props don`t have much cupping to grip the water when the prop gets close to the serfice. A GOOD four blade will give more grip in turns and rough water, overall handling gets better, lower planing speeds, and better hole shot. Normally give up a little top end speed.

Propman is the one to talk to maybe he will chime in, and set us all straight.

[dh99]

To my thinking that 115 on the 1800 and 14 X 19 prop would never hit 6100 RPMS. You have a lot of slip someplace either prop, motor to high, or over trimming. Is the speed GPS? Just because you have a lot of trim dosen`t mean that is where it runs the fastest or best.

When running rough water I don`t want to be trimmed very high I want the bow to cut the waves and not pound into them.

If it`s cavitating in rough water trimmed to high and aluminum props don`t have much cupping to grip the water when the prop gets close to the serfice. A GOOD four blade will give more grip in turns and rough water, overall handling gets better, lower planing speeds, and better hole shot. Normally give up a little top end speed.

Propman is the one to talk to maybe he will chime in, and set us all straight.

It is GPS speed.

I notice that when I trim up too much I lose some speed and if I go even more you can really hear the motor rev and the RPMS go up. and I can also tell by the sound.

As for the 6100-6200 its true. I didn't think it would go so high either. When I was alone the motor actually cut off the over rev limiter kicked in.

I don't know these are suzuki props, maybe the actually aren't the exact pitch they claim to be.



Thanks

DH

[propmann]

I have a DF 115 suzuki on my Lund fisherman 1800 and my motor is venting quite a bit. I have tried it on the top hole and its now on the 3rd hole from the top and the cavitation plate is even with the bottom of the boat.

Its happens more often when I am accelerating and I try to trim or if I am not at WOT throttle. It also happens when the water gets rough.

I have 2 different aluminum suzuki props. A 14 x 19 that runs at 6100-6200 rpms at WOT and 14 x 23 that runs at 5300-5500 RPMS at WOT on the 3rd hole from the top.

Can anyone give me some advice on what to try next.

I think I am going to lower the motor 1 hole.

Should I try a stainless prop and if so does anybody have any recommendations

when you run your #s prop slip is not to bad I would suggest going with a 19 pitch stainless prop. Theres 3 brands that are good for your motor the powertech, turbo, or solas. I would try them in that order. A 4 blade ss would be even better performing but you'll lose a mph or two on top end.

[dh99]

when you run your #s prop slip is not to bad I would suggest going with a 19 pitch stainless prop.

I do not quite understand your statement.

Around what RPM's would a 19 pitch stainless run at?

HOw can you tell if there is slip?

Thanks

DH

[propmann]

You can go online and punch in prop slip calulator, put your rpms, speed, gear ratio which is 2.59:1, prop pitch. As far as going to a ss prop the usually run 150 to 200 rpms less than an aluminum prop in the same pitch.

[TomP.]

[QUOTE=propmann;1128702 gear ratio which is 2.59:1, [/QUOTE]



Good catch I forgot the lower unit gear difference.....