143 Thermostat question
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=43320
Printed Date: May-06-2024 at 10:53am
Topic: 143 Thermostat question
Posted By: gibson1525
Subject: 143 Thermostat question
Date Posted: August-04-2018 at 12:48am
|
I"m working on an overheating problem on my '88 2001 with a 351 PCM. After changing the impeller, cleaning the water filter and inspecting for blockages I changed the thermostat today (a 143 thermostat). There was no difference in the temperature with the new thermostat. It idles at 180, runs 175 at wakeboard speeds and 185 at slalom speeds. I think my ultimate problem is the RWP as it takes about a minute to run suck a 5 gallon bucket dry from the water intake hose. However, before dropping the money on a RWP I decided to test the thermostat on the stove. I put the new and old thermostats in a pot of water and slowly heated it up. They both opened at about 155 just a crack then fully opened about 160. When they were cooled they closed around 140. Is this how a 143 thermostat is supposed to perform? I was under the impression that it should open up at 143. I did this several times with the same result each time from both thermostats. |
Replies:
Posted By: juniorwoody
Date Posted: August-04-2018 at 1:40am
|
Older boats that are running FORD 351's came with a 142deg Marine thermostat. The temp guage would show a running temp of about 160-175 depending on water temp and how accurate the guage was. Those same FORD 351's that came installed with a heater ran a 160+ marine themostat. The guage would read somewhere around 180-190 deg. Helped the heater core get hotter. And then there is the FORD 351 with NO Thermostat it will run about 100deg and be less fuel effiecent. Maybe OK to run in Florida in the summer but not up north. In other words Georgia and NORTH. There is a difference between a Marine and a AUTO thermostat RUN A MARINE ONE. Marine thermostat can close shut but there are 3 small holes in them to allow water to always flow through. I found this on a search and don't know if it is helpful but I think I received a small education. ------------- The value of money spent on new adventure far exceeds the value of money saved for the future |
Posted By: MrMcD
Date Posted: August-04-2018 at 5:04am
|
My 1978 351W we ran for many years. Sold it with 1,500 hours on the clock. It ran right at 140 on the gauge all the time and we used to barefoot a lot behind that boat. Any time it ran hotter than 140 I knew I had a problem, I would search and fix that problem and get back to 140 temps again. Feed a garden hose into your intake and run the engine. If it stays at 140 you have a supply issue. Common supply issue is an air leak on the intake side between the pump and the intake. An old hose or a loose clamp can allow air to suck into the system. If air is sucked in you will not have vacuum to supply your water to the engine. The hoses may be old and stiff. Tighten them when they are warm. You will never get them tight while they are cold. An air leak can be at any connection between the water intake and your water pump. Did you install a quality impeller? Some brands out there don't work even when brand new. Hope this helps. Mark ------------- |
Posted By: gibson1525
Date Posted: August-04-2018 at 10:09am
|
There's no air in the water strainer so I would think at least that portion is fine. I could replace the hoses and see, what happens, it's a lot cheaper than the RWP. My thought was that since it's not sucking much water from a bucket on the intake that the RWP is probably the issue. The only other thing I can think of that I haven't done is look at the transmission cooler to see if there is debris in it. I've never done this before, I'm guessing I just take the hoses off where they enter the transmission and look around for debris?? |
Posted By: SNobsessed
Date Posted: August-04-2018 at 10:36am
|
When you changed impeller, how did the wear plate inside pump look?. If grooved badly, you can flip it over & use the other side. Good luck. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: 8122pbrainard
Date Posted: August-04-2018 at 11:08am
The cam too? The shaft seal may be allowing air in too? Was the impeller you used an OEM? The off brands have caused problems. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
SNobsessed wrote:Posted By: gibson1525
Date Posted: August-04-2018 at 3:25pm
|
The wear plate looked good. I didn't look at the cam or shaft seal. Am I just looking for signs of wear on those? If those are worn am I looking at a RWP rebuild or replace? I'm a novice so depending on the difficulty I'm not sure I can rebuild it. The impeller was a Sherwood from Christie's Marine, same type I've been using for 10 years without any problems. |
Posted By: gibson1525
Date Posted: August-04-2018 at 4:59pm
|
I just inspected the transmission cooler, no issues there, clean as a whistle. I also ran it briefly without a thermostat and it ran at 140. When i slowed back to idle it jumped to just above 150. Does this mean the thermostat has been the issue all along or does it even matter if the RWP needs rebuild or has an air leak? |
Posted By: MrMcD
Date Posted: August-04-2018 at 5:01pm
|
There is a gasket on the water strainers on the intake side. I had one of those leaking air, did not leak water out but air sucked in. Trace the intake lines from the bottom of your boat all the way to the Raw Water Pump. It may go to the water strainer, then the oil cooler and then to the Raw Water Pump. Any air leak along the line could be your cause of high temp. I never had to change the RWP seals so can't advise on that. ------------- |
Posted By: MrMcD
Date Posted: August-04-2018 at 5:04pm
|
When we did hard runs for skiing or barefooting the temp would stay right at 140, when we shut off to pick up or change skiers the temp would rise, engine off to maybe 180. As soon as the engine was started again the temp would fall back to 140 in just a couple seconds. Yours appears to have an issue. ------------- |
Posted By: gibson1525
Date Posted: August-04-2018 at 5:14pm
|
I've checked every connection between the intake and RWP. Everything looks good from what I can tell. The water strainer O-ring looks good but I'll go ahead and replace just in case. It sounds like my problem is a little different than yours. I run 180 pretty much all the time from idle to wakeboard speeds. It runs 185 for slalom and hotter during barefoot runs. Letting it idle will bring it back down to 180 but it never gets cooler than that while running. |
Posted By: 8122pbrainard
Date Posted: August-04-2018 at 6:04pm
Mark, In Brian's first post, he said:
------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: SNobsessed
Date Posted: August-04-2018 at 6:54pm
|
Another thought - Maybe it isn't getting as hot as the gauge says? You could use an IR thermometer to check actual temp. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: baitkiller
Date Posted: August-04-2018 at 7:15pm
We need a "LIKE" button on here. ------------- Jesus was a bare-footer............. |
Posted By: MrMcD
Date Posted: August-04-2018 at 7:40pm
|
Pete, if he disconnected the hose from the bottom of the boat at the intake and put it in a bucket for a new source of water the result is exactly the same to the RWP. It needs suction to pull from either the bucket or the lake. Now if he used a new hose and connected it to the RWP and inserted the new hose into the bucket he could rule out all other leak paths on the intake side of the RWP. I had a buddy lose an impeller at the lake when we had packed in for a 5 day trip. His impeller chewed up and spit chunks into his hoses on the engine side. We had a spare and tools so no big deal right? We dug out what we could. Thought we had all the old impeller chunks recovered. When he fired up again it kept running hot. We ended up pulling the hoses off again and found a few more chunks of the bad impeller still blocking the water flow, the second time we removed the hoses completely off the boat so we could look down through them and found some wedged chunks. At home we could have blasted water through them with a garden hose but at the lake we had to remove them to clean. It can happen even when you think you are being careful. After the more thorough cleaning his boat was good to go. ------------- |
Posted By: Jonny Quest
Date Posted: August-05-2018 at 12:43pm
+1 Get an Infra Red thermometer and do some checking. I would "shoot" temps at the heads, block, block circulating pump, risers, etc. That should give you more important data points to consider. You could have a bad temp sending unit or gauge. The I.R. can help diagnose that. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: 8122pbrainard
Date Posted: August-05-2018 at 12:55pm
And directly next to the temp sender to see if it coordinates with the gauge. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: gibson1525
Date Posted: August-09-2018 at 10:48pm
|
Update. All great ideas, thanks for the suggestions. I tested the RWP and it's pumping an appropriate amount of water so that's not the problem like I originally thought. I talked to the skidim guys and they suggested checking the temp with an IR thermometer also as well as taking apart the exhaust to make sure there wasn't a blockage. The exhaust was clean when I took it apart. When I checked the temps I found the thermostat housing to be 145, near the temp sender 125-130, the manifold risers about 110 all while the temp gauge read 180. So looks like I'll be ordering a new temp sender and see if that does it. |
Posted By: gun-driver
Date Posted: August-09-2018 at 11:22pm
Suggested back on the 4th of Aug |
Posted By: gun-driver
Date Posted: August-09-2018 at 11:23pm
And the 5th.... but what do we know 
|
Posted By: SNobsessed
Date Posted: August-10-2018 at 8:17pm
|
Brian - We would love to know what you find out about the sensor. When you change it, see if you can find an ID #. Either someone put the wrong one in, or it changed resistance due to old age. Information like this helps everyone on the site. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: MrMcD
Date Posted: August-11-2018 at 4:16am
|
Glad you found the issue and it will not be expensive. ------------- |
Posted By: Bri892001
Date Posted: August-11-2018 at 4:46pm
|
I had a similar thing with mine where ultimately a new gauge was the fix. Overall low dash voltage problems, common with these 80s - early 90s boats can cause wacky gauge readings as well. If all of your gauges dip when you blow the horn or turn on the blower or bilge pump, that’s a clue. |
Posted By: gibson1525
Date Posted: August-14-2018 at 2:45pm
|
Update I replaced the temp sender and no luck. It is still reading 180s when the thermostat housing is reading 140s. I have some other voltage issues, the oil pressure gauge reads high and the volt gauge reads low. All of these things started around the same time. So I'm thinking of just rewiring the dash and see what happens with proper grounds to all the gauges.
I definitely have some dipping of several gauges when anything gets turned on so I'm thinking this is at least part, if not all, of my problem. Likely a winter project for me since it's running well currently. I think I'll just enjoy what's left of summer on the water! ------------- 1988 SN 2001 2004 216 |
Posted By: 8122pbrainard
Date Posted: August-14-2018 at 3:09pm
You're not listening!! The T stat housing is where water that's not needed is bypassed to the manifolds so, you may be reading where cool water mixed with hot.------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: gibson1525
Date Posted: August-14-2018 at 5:00pm
|
Correct me if I'm wrong but the bottom of the thermostat housing and right next to the temp sender should read the same temp. I've been taking my temp readings from both those places every time and they are always very close. The top of the thermostat housing is always a fair amount cooler than the bottom. ------------- 1988 SN 2001 2004 216 |
Posted By: KENO
Date Posted: August-14-2018 at 5:42pm
Everything you wrote above is right.  As you mentioned it sounds like an electrical issue since all of your gauges are reading wrong |
Posted By: 8122pbrainard
Date Posted: August-14-2018 at 6:46pm
Brian, Yes, just as Ken mentioned, you are correct. Sorry but I wish you were more specific when you first mentioned the T stat housing. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: gibson1525
Date Posted: August-15-2018 at 12:16am
|
Sorry for the confusion. Thanks for the help, I'm a novice when it comes to this stuff and I appreciate all the solid advice I get here. ------------- 1988 SN 2001 2004 216 |
Posted By: mjajennings
Date Posted: August-21-2018 at 8:15am
| I just read this whole thread, very helpful. Mine (1990 SN) has an issue where temp reads 160 consistently until I turn on the nave lights and then it jumps up to 180- if the boat is at 180 after heavy pulling it reads 200...which has caused me to panic a bit thinking I’m going to overheat on the way Back home at dusk! I heard this might be a ground issue and that I may be able to run a new ground. Any thoughts? Input would be greatly appreciated. thanks, mike |
Posted By: Orlando76
Date Posted: August-21-2018 at 8:34am
|
Perfectly normal due to inadequate ground. ------------- Please support The Cystic Fibrosis Foundation 1976 Ski Nautique 351 Escort 1993 Ski Nautique purple and black 351 HO PCM |
Posted By: mjajennings
Date Posted: August-21-2018 at 9:11am
| Can you suggest any search word or threads about how to remedy the inadequate ground issue?im having a heck of a time with searches as one of the the new guys. Thanks. |
Posted By: KENO
Date Posted: August-21-2018 at 9:22am
|
Let Google be your friend and search correctcraftfan dash grounds and you'll come up with a bunch of reading
|
Posted By: KENO
Date Posted: August-21-2018 at 9:24am
|
Here's what comes up on that search if you click on the link below https://www.google.com/search?q=correctcraftfan+dash+grounds&rlz=1C1FLDB_enUS639US639&oq=correctcraftfan+dash+grounds&aqs=chrome.0.69i59.6801j0j4&sourceid=chrome&ie=UTF-8" rel="nofollow - link |
Posted By: mjajennings
Date Posted: August-21-2018 at 10:06am
| That’s like magic, thanks Keno! |
Posted By: wiscofoot
Date Posted: April-02-2020 at 2:53pm
Is this an agreed on fact? Is the TStat cover gasket a PCM unique part? I know it is different than the standard 351w auto gasket but I'm trying to source one locally and not pay big bucks for slow shipping on a 2 dollar part from DIM. ------------- 1976 Martinique |
Posted By: GottaSki
Date Posted: April-02-2020 at 4:16pm
|
In this age of improvisation, I wouldn't hesitate to cut a gasket from loclly available gasket sheet stock, it's not like it's a head gasket, just warm water under low pressure ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Gary S
Date Posted: April-02-2020 at 5:54pm
First picture is of a PCM thermostat cover gasket (green) and a thermostat lower housing to manifold gasket.  Second picture is the PCM cover gasket and an aftermarket gasket  Here they are on top of each other,at the 1:00 position you can see the aftermarket gasket is cut about 1/16" over.  Is there a difference you be the judge... ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: KENO
Date Posted: April-02-2020 at 6:51pm
|
Wisco You're a power plant engineer I seem to remember. Go visit the maintenance shop and they'll show you how to make a gasket Here a a few pictures showing what you need to do it the "backyard hack" way So easy a caveman can do it, but he'd probably use a rock instead of a ball pein hammer Put the upper housing in a vise as shown, put the gasket material on the housing and lightly bang away using the ball end of the hammer and you end up with a gasket. All 4 holes can be done with the hammer only and if you want to get fancy you can trim things but it's not necessary Don't worry too much about the outside edges, tap enough to get the outline then cut with a pair of scissors 1/32 inch gasket material from your favorite parts store (or maintenance shop) works fine. Ask for rubber fiber gasket material For 6 or 7 bucks or so, you'll have enough material to make a whole bunch of gaskets or screw up once or twice and still have plenty leftover. Then you won't have to buy a genuine PCM gasket or an aftermarket version of it. The automotive ones don't work because the thermostat mounts directly to the manifold and there's no lower housing.....just the thermostat and the cover So.................go for it, you can do it    |
Posted By: Gary S
Date Posted: April-02-2020 at 9:13pm
What ? https://www.oreillyauto.com/detail/b/fel-pro-3607/cooling---heating-16773/thermostats-25043/thermostat-water-outlet-gasket-11350/6edda8a4bfaf/fel-pro-water-outlet-gasket/35440/4303467" rel="nofollow - link ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: KENO
Date Posted: April-02-2020 at 9:51pm
|
Whaddya mean "what" ? What I'm saying is that if you go to the parts store and get the automotive thermostat gasket it won't work between the lower housing and the cover for the thermostat. That gasket will work between the PCM lower housing and the intake manifold though. The automotive gasket has the medium size hole in it and that hole's not needed on the marine engine but the gasket still works between the PCM lower housing and the block Maybe you're saying the same thing? First picture is the cover gasket GREEN and a housing to manifold gasket BLUE Second picture is one on top of the other  
|
Posted By: wiscofoot
Date Posted: April-02-2020 at 9:52pm
|
Thanks guys, I actually bought the one in the link last year and then modified it kind of like Ken described. And yes I know I can make one, just trying to save some time when I unwinterize this weekend and try to efficiently diagnose and fix my issue with water getting by the closed thermostat and not letting my engine warm up and thus not letting me change my oil in the driveway. What I was more curious about is a definitive answer about the T stat, I've seen several conflicting answers. Do the marine thermostats allow more flow when closed than automotive thermostats? Did they come from the factory with holes drilled in them like some of the "performance" hot rod auto ones? Are they all stainless? ------------- 1976 Martinique |
Posted By: KENO
Date Posted: April-02-2020 at 9:59pm
You'll get all kinds of conflicting answers on that t stat question. They're not all stainless, they don't all have holes in them and they don't allow more flow when closed. unless there are holes drilled. A PCM branded 143 degree thermostat is not stainless and has no extra holes And besides, it's kinda tough to find a 143 degree automotive thermostat. Buy a PCM 143 thermostat for the best chance of getting good results
|
Posted By: Gary S
Date Posted: April-02-2020 at 11:10pm
Yea I misunderstood you Ken,for some reason I had it in my head that you could not substitute a thermostat gasket for this special PCM one which in you guy's case is fine. Too many special "marine" gaskets ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: SNobsessed
Date Posted: April-03-2020 at 9:03am
|
Doesn't the thermostat housing have a relief hole cast into it? ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: Hollywood
Date Posted: April-03-2020 at 10:07am
| Yes. When the block is full and cold water is circling in it this hole allows The water you’re still sucking up to get out the exhaust. |
Posted By: 63 Skier
Date Posted: April-03-2020 at 11:52am
|
Not sure why you'd need a stat with relief holes in it for these engines. Only time I've seen that done is for some diesels to improve cold weather warm-up because in around-town driving they wouldn't heat up enough to open the stat, and the heater core wasn't warming up. ------------- '63 American Skier - '98 Sport Nautique |
Posted By: KENO
Date Posted: April-03-2020 at 12:17pm
I think I know what you're asking...........then again maybe not Here are some pictures First one is a 351W intake showing the coolant outlet that the lower thermostat housing bolts to. It's got a bypass hole around the thermostat Second picture shows the mating surface of the lower thermostat housing where it mates to the intake. There's no corresponding bypass hole So there's no way for water inside the engine to get out until the thermostat starts to open, except for whatever might leak by the closed thermostat. Some people sell thermostats with bypass holes to let some water flow, some drill their own holes, some leave it as is Those two pictures show why Gary's PCM gasket with no extra hole and the automotive one with the extra hole will both work . In the automotive setup that bypass path is always there but not in a PCM marine setup. The third picture we could call Hollywood's hole, that doesn't sound too good but I figure it's the one he's talkin' about. It gives flow from the RWP a constant flowpath to the exhaust manifolds whether the thermostat is open or closed. The zip tie through the hole shows how it gets from the raw water inlet connection to the area above the thermostat.   
|