yamaha mph gauge - The Hull Truth

finest times · 09-16-2008, 04:00 PM

I have brand new yamaha's maybe 20 hours on them. Couple of questions I have. First time with outboards so be gentile with me. My MPG gauge just reads --- all of a sudden. some one said to put a piece of wire hanger in a small hole down by lower unit or the "bullet" sound right? what is the bullet? also is 5100 the max rpm I should be getting out them? I have twin 150 4 strokes on a 25 wellcraft cc. Someone said the mph thing is common so I should hook up direct to gps so that wont happen anymore. does that sound right and if so how difficult to do. thanks in advance

A1 Outboard · 09-16-2008, 09:09 PM

I can only guess and offer to point you in the right direction.

Do any other gauges act up when the 3 dash lines appear or does the motor run differently at that time? There could be a ground or voltage problem in the wiring at the gauge itself or in the wiring harness. It could also be the the "pitot tube" hole plug up like someone mentioned to you. Sometimes you have to remove the speedo hose at the gearcase and blow it out.

Since the motors are new and your problem could be electrical or rigging related, take it to your dealer as it should be warranty whether it is a Yamaha problem or a boat builders problem.

finest times · 09-23-2008, 03:54 PM

The holes you are talking about, can I get to them with the boat in the water? can you give me more of an exact location on where they are on the motor. thanks much

A1 Outboard · 09-23-2008, 07:45 PM

The pitot tube hole is the one in the front of the "bullet" of the gearcase. Use a small drill bit by hand to clean out the hole, it goes in about 1" or so. In a sever case of blockage, then the gearcase has to be removed and the vertical hole has to be "drilled" out.