[spinks99]

Hi guys,

Hi guys,

Just got the boat back from the mechanic. He said my prop is too small. I have a 5.0 LX (1995 Z202). He told me I have a 4 blade (I knew that) 17 pitch. He said my engine is running too high of an RPM. He said it was running over 5000. I believe it should be running between 42 and 4800. He suggested a 21 pitch prop.

I've only had the boat out 3 times (bought it last fall). I was running 47 mph (gps) with 4 people, but never looked at the RPM. He figured a 21 pitch would boost my top speed by 6 to 7 miles per hour with a safer RPM speed. I have looked at the "prop talk" forum, but it's information overload. My boat has so much hole shot power it would rival any inboard ski boat, but I don't want to damage the engine at speed.

My question to you guys is what are you running? I want to ski and tube with the kids, but I also don't want to worry about blowing the engine especially if someone else is driving it.

Danny

[mikeyt]

hi Danny

Your recommended rpm range is 4400-4800 for the 5.0L I'm not sure i agree with your mechanic given that you want to pull tubers and skiers. Ideally we would want to know exactly what your rpm's are at WOT to be sure of an answer but i would suggest either a 19" - 3 blade or a 20" - 4 blade which should have you right near the top of your rpm range. For each 2" increase in pitch you will have a 4-500 rpm drop at WOT. The 4 blade will offset the 1" difference in pitch with regards to the rpms. The 19" or even 20" should also add 2-4 mph on to your top end w/out giving up much of your low end punch.

[spinks99]

Thanks Mikey-

I forgot to mention-my outdrive has a 1.65 ratio. The 5.0 LX should have a 1.5 ratio. For some reason my LX was fitted with a regular 5.0 litre outdrive. That may be why he went up a little in pitch. What does anyone know about the high five? My mechanic said he has one I could try.

Danny

[mikeyt]

There are a few members here that have tried or are using the High 5 and if i remember correctly they spoke well of that prop. It can be a little pricey though.

I'm still a little concerned at a 4" increase in pitch as that equates to a drop of 800-900 rpms at WOT. Ideally you want to end up near the upper end of the 4400-4800 range at WOT. If your mechanic will allow you to try a couple of props by all means give them a try and let us know what the results are!