Cold running an Optimax

[Bullet20dc]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ]logsterbass &raquo;</TD></TR><TR><TD CLASS="quote">stupid question. I have a '93 XRI 175. Just had a new waterpump installed & the guy who did it took out both thermostats....Now I'm a little afraid he didn't know what he was doing. Should I put them back? THe water & heads seem to heat relatively quickly upon starting but as u said the block stays nice & cool.
This motor is in great shape for the year---only 2 lbs difference in compression in the cylinders----I'd hate to ruin it...Thanks!</TD></TR></TABLE>

yes you need them get them put back in. The motor won't get up to the right temp and cause several problems not to mention really bad mpg.

[Mr. Bassboat]

sherm, we have the same problem here in our cold water (30-40 deg F). The Opti's warm up at idle but once the throttle is opened up the poppet opens and the water temp plunges downward. As soon as the operator returns to idle and the poppet closes the temp comes right back. The MERCURY guys in tell us not to worry. We've not seen any problems as long as they get warmed up to 100F before taking off.

[EuropeanAM]

Absolutely. you need your thermostats in your motor. They are critical to coolant flow and temperature control. Without them, you will always be cold, and always be running rich.

[madsportinggoods]

That would explain why I've been through 2 powerheads in 2 years on a 2006 225 optimax. Both were piston failures followed by rod failure. Both in cold water and within 2 minutes of blasting off. Great information though...wonder why my dealer or mercury never enlightens people of this information???

[Bullet20dc]

Cold seize will normally happen during the first 2-5 minutes

Cold seize....when the piston expands faster than the cylinder....99% of the time it's caused by a 10 second warm-up and then going WOT. The other 1% happens when the thermostat opens suddenly to allow a rush of cold coolant into the engine, and the cylinder contracts faster than the piston.

[gr8basser]

This question has still NOT been answered. Does the Optimax monitor only one head temperature? If so, why should I spend a thousand bucks for a System Monitor if only one side is measured? Seems to me it will tell me nothing if the other heads' thermostat gets stuck open from debris, and my motor will blow up with or without Engine Guardian or the Monitor. I just bought a 07 Opti 200 and this debris getting stuck in the thermostats is getting to be a real pain in the butt! Sorry for this can of worms, but it needs to be explained in better detail. Sherm?

[rudapa]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gr8basser &raquo;</TD></TR><TR><TD CLASS="quote">This question has still NOT been answered. Does the Optimax monitor only one head temperature? If so, why should I spend a thousand bucks for a System Monitor if only one side is measured? Seems to me it will tell me nothing if the other heads' thermostat gets stuck open from debris, and my motor will blow up with or without Engine Guardian or the Monitor. I just bought a 07 Opti 200 and this debris getting stuck in the thermostats is getting to be a real pain in the butt! Sorry for this can of worms, but it needs to be explained in better detail. Sherm?</TD></TR></TABLE>

That would be nice to know.

[EuropeanAM]

In answer to cyl. head temperature, the Smartcraft Instruments provide a "smart average" of the two sensors.

[copterdoc]

I have a 2000 motor with a 2004 powerhead (pre smartcraft). It had one temp sensor installed in each head, but only one was connected to a wire running to the dash

The second sensor, only provided temp info to the computer/warning horn.

I replaced that sensor, with a multi lead sensor and installed a wire and gauge so I can see the temp from both heads at the same time. It still tells the computer what it needs to know, but I can see if one head is heating up at idle and can throttle up/get on plane, to cool it down before the horn goes off.

[matchangler]

where i live the water is a constant 41f in winter what should i let it warm up to before i gun it ta

[rudapa]

I'd warm it up until it has opened the thermostat and then closed and started warming a second time. That's what I do in the winter here with 38 - 42 degree water. I won't put the hammer all the way down when the water is that cold either. I'm real careful when it's that cold.

[196 Bobby]

I have an 08 200 Optimax. I fish a lot in the winter months. This thread has me somewhat concerned. Do I need to install a water temp. gauge? I don't have any gauges on my console other than the tach, water pressure, amps, fuel, speedo. Where would I find smart tech gauge. Please help!! Don't want to have big problems when it cools down.
Thanks in advance.

[rudapa]

You need to get a smartcraft gauge. Your dealer can order you one. You can watch your temps then and not run it too hard.

[196 Bobby]

Thanks. Will order one today.

[gr8basser]

You wont regret it. I bought one from Sherm, he gave me the best deal by far(comparing with my local dealers). I have an 07 Opti 200 that I run alot of shallow water. The low water pickups on the new lower units tend to pick up debris and stick one of the thermostats. Smartcraft guage will start reading between 90 and 100 deg when one of the thermostats is stuck open. Just pop open the hood and put your hand on each head to see which one is cold. When you get home remove that thermostat and clean it. I bought the small guage to replace my hourmeter(hourmeter built in to smartcraft guage). Best of all you can constantly monitor your temp, so you know when its safe to hammer down and let the big dog roll!!!

[johnmr12]

I have a 2001 opti 225. The plugs that are in there are supposed to work better hot. I'm in the north, so during late fall and early winter, I can't get the engine temp above 100 degrees. After being out a few times, the plugs foul, and I have to pull them and clean them. Is there another plug that is designed to run better cold? It would be nice if I could have two sets of plugs, one for the warm months and one for the cold months.

[Lea]

I'd get thermostats checked. They should be closing so your water temp gets higher than that. As said earlier in this thread, you want temps over 100 or you take a chance on seizing....

[shermsmarine]

If your motor still has the original 120* thermostats you need to do the up date to the new 130* stats...It requires kit # 885599A1 it includes 2 new 130* thermostats & 2 new covers (hsg) along with new gaskets...Spark Plugs are not the problem if your using the recommended IZFR5G's....

[gr8basser]

When did the 130* tstats get introduced. I have an 07 Opti 200, how do I know if I have them. If I dont will Mercury install them free since the motor is under warranty. My motor runs120 ish at cruise and mid nineties at WOT. Just wondering if this is something I should look into. Seems off, 90 deg block and HOT pistons. I would hate to SEIZE the moment.

[johnmr12]

I spoke with sherm from Sherms marine, and he told me to take out a thermostat and the temp rating would be stamped right on the metal. When I pulled it out, there was tiny pieces of wood debris holding it open all the time. I haven't been out on the water yet, but I have a feeling my engine is going to be running hotter now. You guys around Wabash Indiana are lucky to have a marine shop like Sherms. You have no idea how rare it is to find a guy that is honest, generous with his time, and knowledgeable. Trust me, there isn't a single one within hundreds of miles of me.