Over Heat Light & Buzzer Problem

[T-Bob]

My partner has a 150 V-Max that has been giving him a problem. He can run 3-4 thousand RPM with no problem. When he gets it to about 5 thousand the over-heat buzzer & light on the dash come on. The motor will drop cylinders & not get back on plane unless you put it in reverse like you would be cleaning out the lower unit of trash. Water pump & taddle tail are working fine(external anyway). Does anyone have any idea on what to check before he brings it to the shop? Motor is a 2001 model. Thanks for any info.

[jaybo]

Does he have a water pressure gauge? Has he recently changed anything on the setup i.e. engine height, jackplate, etc.? My guess is gonna be poppit valve needs to be cleaned

[hurricane]

Putting it in reverse shouldn't have anything to do with overheat. Might be time for a new water pump.

[T-Bob]

Yes he does have a water pressure gauge. Water pressure is fine, 15psi at 4000 RPM. 25 psi at WOT, when able to run. Nothing has changed with set-up. Just started happening on last fishing trip. No type of warning other than the over-heat light & buzzer. It would not get on plane unless we put it in reverse. Tried 3 different times with same results.

[jaybo]

It is in a safe or limp mode only lets it run up to around 2000 rpm. Most guys that have this problem change or clean poppit valve and it goes away. have you taken the cowling off when alarm sounds and touch heads to see if they are hot. Do a search on this problem and you will find that yamahas are notorious for the overheat alarm going off

[T-Bob]

Thanks for the info guys... I'll check it out & let you know if this works.

[Rich Z]

You may be experiencing a water restriction on the dump/exhaust side. Higher water psi over 25 is typically the indication of a restriction. Poppit valve should open at this point and reduce psi. If water is restricted from dumping out this could definitely cause an over-heat. Clean poppit valve and insert water house on the down flow from poppit valve to clean out any debris.