Cold natured motor on a cold winters day??

[sutor623]

Hey fellas,

So I am continuing break-in on my new powerhead. Put the first 4 hours on it last weekend. Never turned the motor off but went from an idle, to mid throttle, WOT, cruise speed, all over the map. Motor idled down to 600rpms in gear like a champ!!

Fast forward to yesterday. Air temp was from 20-30 degrees all day, 42 degree water temp. I am running double oil, mixing with straight gas. I have to start motor and warm her up for 3-4 mins at about 1500rpms in neutral, then I pop her into gear and off she goes. Idles great, runs really strong. If I come off plane and go back to an idle, she will idle good.

Checked motor temp after a hard run, heads were at 65-70 degrees!!! If I cut the motor off for 1-2 mins, and start her back up, I have to go through the same procedure, but maybe for a minute. Warm her up at 1500rpms or she wont stay running.

1.) Do you think this is simply because of the mixture between the low water temps, and double oil in the gas?

2.) I advanced the timing about 1 degree to keep the idle speed up a bit while it is so cold, is this common practice to change the idle speed from summer to winter?

 

[flyingscott]

your idle speed may change as you break it in that's normal. That being said you are breaking it in under less than ideal circumstances. Remember your motor is always pulling in 42 deg water all the time it is going to run colder. I don't know why you would advance the timing unless you are talking about the idle screw.

 

[sutor623]

I have talked to a lot of fellas on here and the general consensus seems to be that it is okay to break a motor in in the winter time. I do agree with you that is less than ideal temps, but it'll have to do at this point.

It is a V4 looper so the only way to adjust the idle is to advance the idle timing. So it is the idle screw.

 

[dingbat]

I'd be concerned why you have to idle so high to keep it running and why it will not fire right back up.
While hard to start first thing in the morning, it will idle at 750-800 rpm right off the bat and start at the turn of the key the rest of the day.

You water and air temps are pretty typical of mine.

 

[flyingscott]

Check your thermostat that is really the only thing that would be keeping the temps down could be bad. I would also change your plugs more frequently as they will foul out faster with those temps and oil mix. I would also check to see if your motor has more than one plug recommended and if it does run the hotter one.

 

[sutor623]

Dingbat, she will idle down to 600rpms in gear with no issues at all, but I have to run it at a higher rpm for about two minutes before she will stay running at idle. Once there, it will idle with no issues at all, in gear for as long as I want it to. It will fire right back up, just wont stay running without some throttle first.

Scott, I am running the hotter plug of the two that it calls for. The thermostats are brand new as well as the grommets and springs.

I think the issue is due to double oil mixed with super cold temperatures.

 

[flyingscott]

I agree I don't think you really have an issue just the temp. The motor is not going to hold any kind of heat at those temps so having to cold start it every time is normal. Since it runs as good as it does I don't think I would change anything.

 

[sutor623]

I agree I don't think you really have an issue just the temp. The motor is not going to hold any kind of heat at those temps so having to cold start it every time is normal. Since it runs as good as it does I don't think I would change anything.

Thanks Scott, that's good to hear. Just one of the many pangs of winter time fishing I guess!!

 

[dingbat]

Thanks Scott, that's good to hear. Just one of the many pangs of winter time fishing I guess!!

No, running at 70 degree operating temps isn't normal.You should be running @ 120 degrees if your cooling system is operating correctly. Just because your stats are new doesn't mean your cooling systems is behaving correctly. It doesn't take much to stick a thermostat open.

How are you measuring engine temps? Did you rebuild the by-pass circuit while you where at it?

 

[flyingscott]

He will not have a constant temp on that motor there will be a lot of thermostat cycling because of the temps. This isn't a car with a radiator every time that thermostat cycles 42 deg water gets pushed through that motor that is going to cause lower temps at times. I seriously doubt that motor would run good with that low of a temp just a product of it being cold out and cold water temps. He has no running issues and if the temps were that low cold scoring would have happend.

 

[F_R]

Well, let me just say that down here in Florida we don't have air or water temps nearly that low. But even down here, "winter" definatly does cause symptoms described above. And there is so much water that normally bypasses the thermostat, that the motor may never get up to "normal" operating temp. Remember, there is water circulating through part of the powerhead even with the 'stat closed. This is necessary to keep the exhaust cool. In short, I think your motor is normal.

 

[oldboat1]

No, running at 70 degree operating temps isn't normal.You should be running @ 120 degrees if your cooling system is operating correctly. Just because your stats are new doesn't mean your cooling systems is behaving correctly. It doesn't take much to stick a thermostat open.

How are you measuring engine temps? Did you rebuild the by-pass circuit while you where at it?

Winter fishing in cold salt water is a special animal. Stats stick. See salt sludge running down from the exhaust ports. I knew fishermen who routinely pulled stats in the winter when fishing out in the bay -- claimed they always had t.stat issues going between trolling and cruising speeds.

I'm inclined to say 70 degree operating temps are a little low.

 

[flyingscott]

Winter fishing in cold salt water is a special animal. Stats stick. See salt sludge running down from the exhaust ports. I knew fishermen who routinely pulled stats in the winter when fishing out in the bay -- claimed they always had t.stat issues going between trolling and cruising speeds.

I'm inclined to say 70 degree operating temps are a little low.

How warm could those motors run with no stats. I run my 70 hp in similiar conditions on lake Winnebago and the Bay of Green Bay during duck hunting his motor is normal. 20-30 deg air temps whatever temp the fuel is that motor is getting cooled down in a lot of different ways. Even in summer when it's 80-90 deg out you need to cold start the motor after it sits for awhile . Cold motors don't idle but he is idling at 600 rpm his motor is running very well no need to look for problems that aren't there.

 

[oldboat1]

until a stat suddenly sticks shut -- which I think was the larger concern in removing t.stats (that and temps varying -- "sticky" stats.) Think I would try to give it a fresh water flush, at least, whenever I could. Water temps at the hose wouldn't be much warmer, but flushing in a "tank" now and then would give a little heated fresh flush and a temp check.

 

[dingbat]

Winter fishing in cold salt water is a special animal. Stats stick. See salt sludge running down from the exhaust ports. I knew fishermen who routinely pulled stats in the winter when fishing out in the bay -- claimed they always had t.stat issues going between trolling and cruising speeds.

Winter is prime time Striper fishing here in the Chesapeake. As an avid Striper Fisherman and part time Guide for the past 20 years I have first hand knowledge of the problems you speak.

Most "exhaust creamers" are running pre-mix. Never had problem with any of the injected engines I've run.

I had a Merc 175 that would overheat while trolling in cold water. Called Merc and they recommended replacing the 140 thermostats with 120 degree. Didn't fish that boat more than a handful of time in cold water so I just "goosed" it now and then to open the stats to cool it down.

The Ocean Pro I run now doesn't seem to care one way or another after I get it started in the morning. Been running it since 2002, easily 100+ hours a winter.
Never had a temperature related problem with this motor.

 

[oldboat1]

Interesting, dingbat. I was more of a fair weather fisherman (Annapolis), but had two slip mates running in the winter, both with Ocean Pros. They didn't seem to have any problems either -- same as your experience. Don't recall much re. Mercs, but had a friend running an older Yamaha, and he complained about wonky heat ranges running in cold water.

Maybe the rich mix is a factor for Sutor -- maybe a number of factors coming together at the moment.

 

[flyingscott]

I agree but I wonder how many people mistake cycling stats for sticky stats. When you have a motor running the temp comes up and the thermostat opens and the warm water gets replaced with cold the stat slams shut again. That cycling happens so much more in cold water it takes the stat longer to open and a much shorter time to close. It's just the thermostat doing it's job at those temperatures and motors run colder at an idle. Wondering what the temps would have been right after a 10 min wide open run but he has a brand new powerhead so can't do that yet. And the OP has not had any problems with his engine just said it ran great not a temp issue motors don't idle with 70 deg heads if they did you wouldn't need a warm up lever.

 

[sutor623]

Wow guys, sorry for all the confusion. Interesting debate for sure.

Dingbat, you asked if I rebuilt the bypass circuit. The bypass circuit on these motors runs right behind the thermostats, so when you change the thermostat, grommet, and spring you are effectively rebuilding the bypass circuit. This motor has had both sides replaced.

I checked the temp of the motor with an IR temp gun that is reliable. I pointed the gun at the thermostat covers on both heads. Just after I pull off plane after a solid run I pulled the cover off and had temps of 70-80 degrees at that spot. If I checked the cylinder heads just beside the spark plugs it would be more like 100-110 degrees.

After letting the motor idle for a minute or two, the temp at the thermostat cover fluctuates from 120-135 degrees.

An interesting point was made about "exhaust creamers". I assume this is talking about pre-mixers. These motors (with VRO) run a light oil mixture at idle, maybe 100:1. This mixture goes up to 50:1 at WOT. A pre-mix motor is idling at 50:1. Now take a double oil, premix motor (mine) and we are running 25:1 at IDLE!!!! Just thought this was an interesting point.

On top of this, I had an issue where my quickstart would jump in and out until the motor either A.) warmed up or B.) had the white/black wire grounded. I disengaged QS. So now I HAVE to run the motor at high idle to get it to warm up and stay running. It'd be nice to have the QS reconnected so that I could "hear" the motor drop from 1200rpms to 8-900rpms at idle. Then I would know that the head temps were at least 96 degrees.

I also think re-hooking up the VRO would help with the cold idle.

Maybe the combo of the cold, high oil, and no QS is compounding and amplifying this issue. Kind of scary how real the risk of cold seizing a water cooled motor is in the winter time. I think the solution is to stop bitching and let the motor warm up for a few SOLID minutes before taking off. My main fishing buddy has a 4 stroke so he is always giving me hell about this................

 

[phillnjack2]

dont matter what the temp is outside the top of the head should be around 140 degree, the thermostats are the 143 opening ones in those motors and the thermostats let the water out of the heads not in !!! so if its mines 20 outside it still should not open until 140 ish. now adding more oil should not make much difference to the temp, maybe 1 or 2 degree at most, it obviously will just smoke a bit more.. once you turn the engine off, then on a cold day it will rapidly cool down and need to warm up again. the mid section will get real cold straight away and heat rises so does the coldness of the water.
if you run the engine at around 1,000 rom for 2 minutes once the choke is off then the temp should start to rise, do not run high rpms until its warm.
now keep it running and take the lid off then right on top of each cylinder use the infra red temp gun, this should show around 140 to 140. when running at full throttle the temp will go down a touch and water should be shooting out the two holes at the top of the mid section at the back. if any water other than a tiny little drip is coming out of those holes at 100rpm and under then the bypass is stuck open .... personally I would now go straight to 50=1 fuel to and see how she runs.
and check the temp at top of cylinder head not down at the thermostat housing. ..to be honest I think it will turn out to be perfectly normal.

 

[flyingscott]

. personally I would now go straight to 50=1 fuel to and see how she runs.

Are you going to warranty his brand new powerhead if he does that. Stick with the break in the manufacturer recomends for your powerhead. There is no way that motor holds 140 deg not in 42 deg water. If the motor manages to get to 140 degrees when the thermostat opens the motor is filled with 42 deg water that's a 100 deg swing. His temps were taken at the hottest part of the head the spark plug because it is attached directly to the combustion chamber and it was 110 there. Air temp absolutely does matter to a 2 strk motor as they use the fuel and air mixture to cool the crankcase. There is nothing wrong with his motor it is running normal just running in cold water.