Prop diameter question

[dpdiver]

Just installed !997 Yamaha s200 txrv on A 26" stainless marine bracket. Came with used 19 pitch stainless prop, dosent say diameter.Breaking in full throttle 45 mph at 5000 rpm, wot 6000. Prop has vibration between 1100 and 1400 rpm, engine out of gear same throttle no vibration. Installed new 15.5 apollo prop, but it hit the anode(hand power). What diameter prop does this motor require? pitch? :%: THANKS

 

[walleyehed]

Re: Prop diameter question

The Tab needs to be altered slightly by grinding, or removed.
I believe they make a replacement anode to allow higher Rake props as well.

 

[Crownie2]

Re: Prop diameter question

I notice that most of the larger Yammy props are 15 1/4" in diameter.

 

[walleyehed]

Re: Prop diameter question

The design of the blade has more to do with tip placement than diameter...
I still see MANY people getting hung hard on diameter. It serves a specific purpose, but in the case of hitting the anode, most times it's because of higher rake.
I have 15" props that don't hit, and some 14-1/2 or 14-3/4" that do.
I've rebuilt my tab to except those props, but flat plates are available for most, and some have extended tabs to clear.
It's very easy to take a grinder and remove 1/8-1/4" from the tab and then reshape for proper water-flow.

 

[Boomyal]

Re: Prop diameter question

The design of the blade has more to do with tip placement than diameter...
I still see MANY people getting hung hard on diameter. .

Trying to get a clarification on this very point. 'twould seem that diameter (blade shape aside) would be as equal a part as pitch. Where am I wrong?

 

[walleyehed]

Re: Prop diameter question

I can run 15-1/2" props that are 2" in front of the tab, and yet a higher rake blade design (laid back) in a smaller diameter may hit the tab but only be 14-1/2" diameter.
Now, there "may" be some cases where the blades may actually hit the AV plate, in which case it would be considered a mis-matched application.
It's just like the Solas Scorpion props when they came out...on just about every engine manufacturer that was using a tab..the prop hit it. The tab has to be changed out or modified.
This really isn't all that uncommon, but if it's on a big boat, it better have a very high HP/Weight ratio or it's likely a prop with too much rake for that rig anyway.