1986 evinrude vro 90hp not fully revving at wot

[Camzank]

I recently purchased a 1986 procraft 1540v with an evinrude vro 90hp. The motor is starting and running without issue. At top end it’s only revving to around 4000 rpm. It goes thru momentary “full revs” if that makes sense. Like it wants to fully open up but it hangs at about 4000. This is my 1st outboard and I want to learn the stuff myself. Any suggestions would be appreciated.

 

[racerone]

Start with posting your compression numbers.-----You could also run with a timing light to see if one cylinder has intermittent spark.

 

[Boobie]

Do a cylinder drop test on it.

 

[timguy]

Welcome. Do you know how to set up a video? We can't take the boat out for a spin, but a video can really help. Have you checked the spark plugs? Keep them in order so you can observe any differences between cylinders regarding spark plug color. Do you mix the gas/oil, or is the VRO still functional. I like that you first came here for direction.

 

[Camzank]

I know this is off topic of the post but I don’t really understand what the vro system actually does for the motor

 

[Camzank]

Ok I looked it up and the vro system is deleted. Just doing 50:1 mixture.

 

[Camzank]

I ran the boat for the 1st time yesterday so I’ve got a lot to learn about it. It’s got a hydro foil on the lower unit. It seemed to open up when the front would launch up from a wave and then back down again when the boat was back in the water. Is it possible that me not trimming up enough led to it not revving very high? I didn’t trim up very much. On my Glastron ski boat the steering loosens when you have trimmed up to the perfect amount. Is that also the case with outboards?

 

[timguy]

Yes, proper trim is very important. Trim up to just before porpoising. Also if the VRO has been destroyed or disconnected, we need a few pictures of how it was done. Perhaps it is starving for fuel at full power. To post a photo here, you simply reduce size to under 1000k.....create a file for your boat pictures, then go to "advanced".....on the bottom of your post, then up above just tap on the "paperclip" icon, then follow prompts to attach your photo, or photos.
By the way, did the seller tell you why the VRO was disconnected? Perhaps it was flooding the motor with excessive oil. This is quite common, and it often involves a very simple and inexpensive fix.