Not reaching proper RPM 1993 4.3

[bassjbl]

hello, trying to work out a problem here, I thought I wasn’t reaching rpm sitting at 3300 because my prop was a little beat up “ I believe it was factory 15” 15 pitch” so I replaced it following a guide and now have on a 14.5” 19 pitch. But still am sitting at 3200 rpm at WOT. Chenged spark plugs just because I haven’t, and exact same. What is next? Timing? If I put my prop in nuteral and throttle it very quickly goes over 4K as it should.

 

[Maclin]

What MPH are you at with the 3200 rpm's? Is the tach accurate? What size and type of boat are we talking about?

Is this boat new to you? If not, has it always acted this way? Or has it been able to reach 4400-4600 RPM's in the past?

 

[ThomW]

If you went from a 15 pitch to a 19 pitch, you're losing rpm's. As a general rule, each inch you raise pitch, you drop around 200 rpm's--give or take. So if you go back to a 15 from the 19 you have on now, you should gain almost 800 rpm's.

 

[alldodge]

I think your tach is bad. Find a hand held one and check it