40 HP Yamaha on a 18ft Bass Buggy Pontoon

[dtacmed]

My question is my tach is only showing 2500 at full throttle. However its running at about 21 mph. Can anyone tell me what speed I should be running. Everyone I have talked to say I should be running about 5000 at full throttle any ideas.<br /><br />Thanks

 

[Moving Target]

Re: 40 HP Yamaha on a 18ft Bass Buggy Pontoon

Sounds like a Tach porblem. Is it a Yamaha Gauge or an aftermarket? I bought a used boat, and someone replaced the tach, but they had it set for a 6cyl motor, not a 4cyl motor.

 

[NMplayer]

Re: 40 HP Yamaha on a 18ft Bass Buggy Pontoon

I don't see any way you could run 21mph at 2500, Tach is goofed up.