rpm increase

santigo

Member
Joined
Oct 21, 2006
RO Number
23988
Messages
77
I have a 3067 santigo with twin I/O recently my port engine rpm has begun to vary. I first noticed on a following sea on the hudson river and thought it was cavitation. We went out the next day and had the rpm up to 3000 with no problem Yesterday we went out and the rpm varied by but not by much. Any sugestions
 
Bob may be right, Dan, but first, since you were in a following sea, is it possible you were just experiencing what a lot of heavy boats feel whereby you are in effect surfing on the seas and your RPMs increase and decrease periodically as the wavetrains pass underneath??? I would imagine you have experienced this situation before, though...

If not, lets look at Bob's point. If you see RPM going up substantially, and the boat tending to turn towards the overspeeding engine (because the other side is still pushing the water properly), then perhaps there is a problem with the hub. How far did you drive that day? Did you have a lot less fuel in the tank the next day when it seemed okay? My friend's boat used to work just fine with 2 people on board and a 1/4 tank of gas. Put 4 people onboard and a full tank and bingo - the hub would spin and he'd have to limp home...

There is a lot of crap in the River lately - any chance you hit something???
 
You can check for a spun hub by marking a stright line on the hub to the housing with a permanent markier, ir even a small scrtach with an awl. Take a quick spin, rev the motor hard, and then recheck your line. It should still be straight and connected, but if it's not, then the hub is spun.
 
I didn't hit anything and I agree about the cavitation with a following sea. I thought I may have spin the hub as well. But when I revived up to 3000 rpm The rpm was ok did not take off. The swim platform is such that to access the outdrive I have to be hauled. Let's see what happens this weekend. Thanks guys
 
Ever try getting into water you can stand up in and raising the outdrive for access?
 
I have the same boat and drives. You can get at the props by lying on the platform with your arm in the water up to your shoulder. I did it 2 weeks ago twice to test some props. You can just see the bottom of the prop by looking and you can get them off by feel being careful not to drop any thing. If you switch the props over at least you can tell if it is drive or prop problems. I spun a hub on a previous boat and if left too long, the thrust washer will wear down the bevel on the driveshaft and thats a few bucks to fix!
 
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