Go Back   TeamTalk > General MasterCraft Topics > General Discussion

Reply
 
Thread Tools Display Modes
  #1  
Old 10-04-2018, 01:47 PM
quattrotto quattrotto is offline
TT Newbie
 
Join Date: Jul 2018
Boat: 1991 Prostar 190
Location: Northwest
Posts: 11
Winterization - 1991 Prostar 351W not getting to operating temp

Hey all,

Doing my first winterization of my new-to-me 1991 Prostar 190 with a 351W. Doing this in my backyard with the "intake hose in a big bucket of water being filled with a hose as the motor runs method"....temperature on the water has always hovered around 150 degrees on the temp gauge, but I can't get it past 120 in my backyard....when I juice the throttle a little to a higher idle (around 1200-1500 RPM's) the temperature actually decreases slightly. Back to normal idle (700-800 RPM) it comes back up to 120. Had the engine running for at least 15-20 minutes without it going above 120. So ended up just changing the oil and tranny fluid, but didn't fill with AF since couldn't be sure the Thermostat was opening.
So, what could be causing this? I'm sure the water coming from the hose is colder than the lake water, but would it be that drastic as to cause a 30 degree drop in engine temp? Is my thermostat stuck open somehow? Should I just pull the thermostat before I run the AF to be sure all is getting through to the block? I don't want to screw this up so any thoughts and suggestions are much appreciated!
Reply With Quote
  #2  
Old 10-04-2018, 02:49 PM
EricB EricB is offline
MC Fanatic
 
Join Date: Jul 2004
Boat: 77 S&S, 1983 S&& PS, and now a 98 Anniversary S&S LT1 PS
Location: St. Paul, MN & Balsam Lake, WI
Posts: 735
Running the engine to operating temperature is done to drain and change the engine oil. If that has been done, then it's time to install anti-freeze. This step should be done on a COOL/COLD engine, not hot. You would be wasting alot of coolant if you expected to do it on a warm engine.

So if the oil change is done, time to drain the water from the engine. Open the engine drains and allow water out. Let it drain and cool. If you have a heater, make sure you drain it also. Make sure you get as much water out as you can by draining (you may need to remove some hoses too).
Once you feel the water is mostly been drained, the next step is to do the "intake hose into a bucket" filled with anti-freeze. 3 to 4 gallons will be more than sufficient for an older 351 like you have. You can pull the thermostat out if you wish, but not required. Suck all the coolant in, and when it starts to come out the exhaust it's done.

The raw waterpump and the engine circulating pump will fill the engine with anti-freeze, no matter if the thermostat is opened or closed. It does not matter. The pumps will provide flow to fill the empty cavities and provide enough for the muffles to prevent a hard freeze in them.
Reply With Quote
  #3  
Old 10-04-2018, 03:12 PM
quattrotto quattrotto is offline
TT Newbie
 
Join Date: Jul 2018
Boat: 1991 Prostar 190
Location: Northwest
Posts: 11
Thanks EricB for the clarification. I'll follow your recommendation this afternoon. Still doesn't explain why I can't get the engine temp past 120 degrees on the trailer, though. I drained the block/hoses/heater/shower a few days ago prior to my winterization as a precaution as we were getting into the low 30's/high 20's overnight here in MT the last few days and my dreams of one last day on the water this fall failed to materialize. So there was no water in the block when I started it up on the bucket, and there seemed to be no other issues (started right up, idled fine, revved up to 2000 rpm fine, water coming out exhaust fine, no leaks anywhere, and temp went to 120 in a reasonable timeframe).
So I guess I'm wondering if something happened to the thermostat (or something else) after draining the block the first time?
I am planning on draining the AF after I run it through the motor, seems to be the preferred method around here in NW MT....
Any thoughts? Would like to figure it out now so I can hit the water in the spring without issue. Thanks!
Reply With Quote
  #4  
Old 10-04-2018, 03:27 PM
Miss Rita's Avatar
Miss Rita Miss Rita is offline
MC Devotee
 
Join Date: Jul 2009
Boat: 1992 ProStar 205, 1991 Ski Pro
Location: Black Hills
Posts: 1,373
Quote:
Still doesn't explain why I can't get the engine temp past 120 degrees
Point sources of possible problem:

1) bad thermostat
2) bad sender
3) bad gauge

Replacing the thermostat is cheap and easy, worth a try. Replacing the sender isn't much tougher. It would be a lot more worrisome if the engine was running hot for unknown reasons.
Reply With Quote
  #5  
Old 10-04-2018, 03:33 PM
babymoore3's Avatar
babymoore3 babymoore3 is offline
TT Enthusiast
 
Join Date: Apr 2005
Boat: 1988 Tristar 190
Location: IL
Posts: 110
Engines don't produce a ton of heat at idle versus your cold intake water (assume 40-50F). Maybe higher RPMS for a while or feed exhaust water mixed with hose water back into engine using some PVC pipe Ts and valves. Higher RPMS on a hose will suck the hose shut.
__________________
1988 Tristar 190 - Looking to upgrade to more family friendly boat....
Reply With Quote
  #6  
Old 10-04-2018, 04:32 PM
quattrotto quattrotto is offline
TT Newbie
 
Join Date: Jul 2018
Boat: 1991 Prostar 190
Location: Northwest
Posts: 11
Thanks for the replies....
As this was never an issue out on the water, I may just winterize as is and look at replacing the thermostat as a preventative measure in the spring. I hate to mess with things when the conditions are inconsistent (such as "on the water" vs. "on the trailer").
Reply With Quote
  #7  
Old 10-04-2018, 05:16 PM
jharmon203 jharmon203 is offline
MC Fanatic
 
Join Date: Oct 2015
Boat: 2000 X-star
Location: Midwest
Posts: 524
Quote:
Originally Posted by EricB View Post
The raw waterpump and the engine circulating pump will fill the engine with anti-freeze, no matter if the thermostat is opened or closed. It does not matter. The pumps will provide flow to fill the empty cavities and provide enough for the muffles to prevent a hard freeze in them.
Are you absolutely certain about this statement? If you aren't going to let the engine get back up to temperature, then the thermostat needs to be out correct? Otherwise you aren't getting antifreeze into the actual engine. This is the point of the thermostat. You don't want your coolant (raw water) to enter the engine until it's needed otherwise it's going to make the engine run at a low efficiency.

One of the number one things I have read about cracked blocks is people start their cold engine up, they run antifreeze into the engine and see it spit back out. The problem with this is that it didn't actually enter the engine due to the thermostat not being open.
Reply With Quote
  #8  
Old 10-04-2018, 05:21 PM
jharmon203 jharmon203 is offline
MC Fanatic
 
Join Date: Oct 2015
Boat: 2000 X-star
Location: Midwest
Posts: 524
quat, what you are describing sounds like the thermostat is opening at the point the temperature dips down and it should. Once the thermostat opens, it allows the raw water that is cold into the engine to cool it down and you will see a slight dip and it should hover at whatever temperature your thermostat is set to open at. I would agree that 120 seems a bit low, so perhaps you should check into getting a thermostat replaced as that isn't an expensive or difficult thing to change. You might want to get yourself an infrared heat gun sensor and shoot it at the thermostat housing to compare that temperature with the one you are seeing on your gauge. Perhaps your guage is way off and your thermostat is opening at the correct temperature.
Reply With Quote
  #9  
Old 10-04-2018, 05:24 PM
jharmon203 jharmon203 is offline
MC Fanatic
 
Join Date: Oct 2015
Boat: 2000 X-star
Location: Midwest
Posts: 524
ha, to further make things fun, one thing you could do is go an get a big bottle of food coloring and color your raw water you have on the hose. Turn the engine on and let it suck up that water. If you drain your manifolds and see that color of water coming out you know you are getting past the thermostat and getting fluid into the engine vs just bypassing it back into the ground or bucket.
Reply With Quote
  #10  
Old 10-04-2018, 05:25 PM
quattrotto quattrotto is offline
TT Newbie
 
Join Date: Jul 2018
Boat: 1991 Prostar 190
Location: Northwest
Posts: 11
jharmon203 states what I have always understood....so some clarification would be awesome! As I will be draining the block, heater and hoses of AF before storage anyway, I would assume I'll be able to see if the AF ended up in the block. I may just run it up again to the 120 degrees before draining the water and refilling with the AF....
Reply With Quote
Reply

Tags
351w, prostar 190, temperature, thermostat, winterize

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -4. The time now is 08:12 AM.


2018