Not Enough Max RPM's Bad?

[jncbama12]

My Honda BF50 50HP 4 -stroke on a 16' Carolina Skiff has a max rpm rating of 5500 to 6000. Mine was turning 6200 at full throttle and would cavitate a couple of seconds when trying to get on plane. Also, it would not plane off with 3rd person in the boat. I had the prop pitch increased by one inch and added a little cup. Now, no cavitation, comes up on plane great (haven't tried it with a 3rd person yet) but I lost 1200 rpms at full throttle which now is turning 4900 to 5000 rpm's. Also, I didn't lose any top end speed which surprised me. I hardly ever run it at full throttle.

Even though their seems to be a 100% improvement, is this bad for my motor?

 

[Jake Windemere]

Re: Not Enough Max RPM's Bad?

5K of RPMs is not lugging the engine, so I would guess that you are doing well.

Once you lose a little diameter on your prop from sand/silt you will likely regain your top RPMs.

I wouldn't worry about it.

 

[JUSTINTIME]

Re: Not Enough Max RPM's Bad?

no way u dropped 1200 by 1" of pitch

 

[jncbama12]

Re: Not Enough Max RPM's Bad?

Believe it! The tach doesn't lie. Keep in mind my pitch was only 12" with hardly no cup. Even the guy at the propeller shop said it's now wonder I was having problems. But that's what caame with the boat and motor. It looks like a totally different prop now.

 

[hondon]

Re: Not Enough Max RPM's Bad?

Tachs DO lie.That boat mounted tach is a guidline and should only be considered as such,especially with that 50's unique ignition.I have seen them off at least 200 rpm when compared to a shop tach.