YOU ASKED FOR THE RPMS WELL HERE THEY ARE HELP

[Todd from Tenn]

I asked what my top speed should be for my 2004 187cx with with a 175hp yamaha. You informed me that you would need the rpm at full throttle. Well the rpms at full throttle are 4900 and 51mph. I'm running a 3 blade prop with no info on it I can find. So please give me your thoughts. thanks in advance

[Bruce2]

Well for 1 you are about 800 rpm shy of what you should be running WOT....Since we don't know what prop pitch you have, we can assume one of 2 things..either you have a motor problem or you are way over propped....do you have a jackplate? and what is your prop to pad ?.......you may have told this info in another thread but would make it easier if you posted all that info here also...

[HaulinBass]

Welcome Todd. Appears like you have your assignment.

[Dan21XRS]

Easiest thing to do is take the prop to a local shop and have them spec it out for you... Until you know, or get a known prop you're just dancing in the dark... Dan

[n2ratfishin]

I posted last time I'd run a 24 Tempist (Fury wasn't out when I had that boat) and you should be running mid 60's. Running by yourself you are lugging the engine at those RPM's and that's one of the hardest things you can do to it.

[grout-scout]

And then to get deeper into the situation...could be a motor issue and have nothing to do with the prop whatsoever.

[Royjulius]

First thing to do, as said above, is get a known prop. At 5000 ft, 23 Tempest works best for me. 3.125 below pad. When I'm on the MO river, at 1700 ft, I use a Tempest 25.

[STLBassBuster]

That should be a 63+ mph rig. Make sure your throttle cable is working properly, no other engine issues, then focus on props and jack plate heights.

[rboren]

That should be a 63+ mph rig. Make sure your throttle cable is working properly, no other engine issues, then focus on props and jack plate heights.

THIS!!

[getfished]

That should be a 63+ mph rig. Make sure your throttle cable is working properly, no other engine issues, then focus on props and jack plate heights.

+2 . Rpms should build to somewhere in the neighborhood of 5600-6000 depending on specific motor model specs. If your throttle is opening completely and the motor seems to be running OK you probably have a prop that's pitched too high which will prevent the motor from revving up to full rpms.

What part of Tn are you in ? Might be able to assist you if reasonably close. A 24 Tempest ought to be about right if you are running a 175 motor and 3 & 1/2" prop to pad is a good starting point.