135 Mercury Optimax overheating issues

[caribbean boater]

This is my first time here. Over the last three months, I have been reading this forum, and I found your comments and suggestions very useful on my new boating experience. I have a 2007 135 Optimax on my 2008 Trophy 1903.Recently, I have experienced some issues with the overheating alarm (the continous sound). The Guardian System went off 3 times before I changed the impeller kit this weekend.

Now the alarm doesn't sound anymore but when I was entering to the to the marina no wake zone after navigation (I mean, when the rpm's goes down from 4,000 to 1,500) I saw some vapor-smoke that comes from the inside of the outboard through the back hole or exhaust-water discharge. It's not a huge or dense smoke and it seems farely clear. That vapor-smoke is similar in density but lesser to the vapor before the exchange of impeller.

I don't have temp gauges, just my eyes and ears.

My question is this is normal? I have to change the thermostats? This is related with oil-gas mix/VRO? What about poppet valve? Again, I would appreciate your comments and suggestions.

 

[blackbox]

Re: 135 Mercury Optimax overheating issues

it is a good idea to change the impeller every yr. if you go longer than 2 years you will have an intermittent over heat prob. the motor will go into gardian mode and cut back power to prevent any damage to the motor. the popet valve diaphram should also be replaced. merc. wants us to replace thermostats, they are high quality stainless steel and sometimes can be cleaned and reused.(i did not say that). the steam/smoke sounds normal. the 135 opti has a good track record and is a solid,fuel efficent motor.

 

[caribbean boater]

Re: 135 Mercury Optimax overheating issues

Thank you Black box. I'll try to clean or replace thermostats. Where is located the poppet valve? Do you know the part number?