Engine Temp for a 351
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=1865
Printed Date: June-26-2024 at 6:37am
Topic: Engine Temp for a 351
Posted By: keuka1
Subject: Engine Temp for a 351
Date Posted: June-13-2005 at 8:12am
Hey board members I was hoping you could help me by telling me what the engine temp should be after warm up for a late 80's 351.
Currently I am running at 110-120 which seems a little low to me.
Thank you
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Replies:
Posted By: AWhite70
Date Posted: June-13-2005 at 11:20am
It depends what temperature thermostat is in your boat. I've got a 160 deg. stat in my '79 (original equipment was 140 something), and mine runs 160-170.
I believe your boat originally would have also had a 140 stat, either way you're running too cold. Replace your stat with a new 160 stat, skiDIM has them.
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Posted By: Jim_In_Houston
Date Posted: June-13-2005 at 1:23pm
I have read, on this forum (I think) that if you run is salt water you should install a 143 deg. thermostat.
BTW, does anyone else's temperature continuously cycle over about a 20 degree range? While driving my boat at any speed I can tell when my thermostat opens by watching the temp gauge. Is this normal? The cycle from high temp to low temp and back to high takes about 5 minutes.
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Happy owner of a '66 and a '68 Mustang
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Posted By: Guests
Date Posted: June-13-2005 at 1:25pm
I do not use the boat on salt water, just the Fingler Lakes in NY.
My temp does not move after warm up.
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Posted By: AWhite70
Date Posted: June-13-2005 at 2:10pm
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Jim_In_Houston, that kind of temperature fluctuation is pretty normal. My '79 does the same thing. Depending what I'm doing the temperature runs from about 155-175. When starting the engine after sitting for a few minutes it will jump to almost 180 and then creep back down to 160 (with the engine off all of the water in the block gets heat soaked). When I'm underway at a decent speed the gage stays pegged at around 165
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Posted By: Jim_In_Houston
Date Posted: June-13-2005 at 2:23pm
Thanks.... That's exactly what mine does. The temp seems to register very high (around 180 - 190 degrees) after it first warms up and then quickly drops back down into the range where it begins cycling up and down. I was suspicious of my theremostat (but not suspicious enough to pull it).
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Happy owner of a '66 and a '68 Mustang
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Posted By: 79nautique
Date Posted: June-13-2005 at 4:23pm
The only time I ever see mine go above 160 is when the strainer is clogged other wise it is within 5 degrees of 160, makes no difference if I'm putting around at 2500 or ripping it at 5500 rpm it will stay at 160. I would say that your passages are getting a little clogged or your thremo stat is slow to react. If you have 160 thremo then it's going to open at 160 and your engine should never be above that temp it should start cooling from that point. 20 degrees over your thremostat seems high to me and indiocates a water flow problem. Then again it could just be a older sending unit and/or guage.
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http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique
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Posted By: dmoney
Date Posted: June-13-2005 at 5:19pm
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I have a 92' Ski Nautique that I finally got out this year (wife just had a baby!). Replaced the impeller last year, but it still seems to be running oddly temp wise. When opened up between 28 and 35 mph, the gague reads between 160 and 170. When I was idling or pulling into the lift, it moved up over 180 and approached 200. Any ideas? Thanks.
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Posted By: nms1991
Date Posted: June-15-2005 at 1:35am
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Check your water sstrainer bowl make sure it is tight and it has the oring in it and check to make sure the hose fittings are tight in the housing.
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Posted By: Jim_In_Houston
Date Posted: June-15-2005 at 11:13am
dmoney, mine did that when I first acquired the boat. The problem was the raw water pump was worn. With the boat moving pressure would force the water up to the raw water pump where it would begin to pump. The raw water pump did not have enough umph (pronounced ooommmppff) to prime itself. After water reached it (from me driving the boat or gunning the engine) the pump would begin to work. Until then the engine would overheat but as soon as I began to drive the temp would fall to normal. An impeller replacement did not fix it. I had to polish wear grooves out of the body and replace some kind of bronze part, that came in the complete rebuild kit, and fits into the pump cavity. I think I bought it from skdim. I had to dissasemble my pump to find some numbers stamped on the flange which the seller could use to match up to the correct kit (my pump is a 1968 vintage and parts are still available for it.)
(But nms1991 may be right on - it sounds like it could be a air leak.)
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Happy owner of a '66 and a '68 Mustang
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Posted By: 79nautique
Date Posted: June-15-2005 at 2:49pm
going faster in the boat is not going to make the water enter the pick-up any quicker, it's not a scoop it's actually a reverse scoop. Anyway the reason it picked up water was because the pump was spinning at a higher rpm thus creating more suction. Inspect the strain and trany cooler if you don't have a strainer and inspect the impeller for ware and replace if needed.
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http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique
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Posted By: Nautique2001
Date Posted: June-21-2005 at 10:18pm
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110 - 120 is low. My 1986, 351 runs between 160 - 170. My old 1980, 351 ran about 160. The plugs won't burn as nice if it's running cool. How's the thermostat? At least you're not overheating!
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Posted By: GABOY
Date Posted: June-22-2005 at 11:58pm
So if my 1985 SN is running under 120 constantly this could mean a power loss?
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http://www.correctcraftfan.com/diaries/details.asp?ID=811 - This is my boat, 1985 SN
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Posted By: Jim_In_Houston
Date Posted: June-23-2005 at 12:42am
Yeh. 120 is too low. It could be faulty sending unit but my guess is it's time to change your t-stat.
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Happy owner of a '66 and a '68 Mustang
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Posted By: keuka1
Date Posted: August-11-2005 at 3:14pm
Changed T stat and it is now running at 140 and the carb is not "loading" any more.
Thanks for the input.
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