Engines running cool - wont heat up

Discussion in 'General Discussion' started by Wayward Sun, Jul 3, 2022.

  1. Wayward Sun

    Wayward Sun New Member

    29
    May 5, 2022
    280 Sundancer 2004
    Twin 4.3 Alpha Gen 2
    Hey everyone. Finally got the boat back out again (2004 280DA Twin 4.3's). Engines seems to be running too cool/cold. Lake temp = 82 degrees, Air temp = 90 degree's. Both engines running ~113 on digital smart gauge and same on analog gauges. Impellers replaced this season. I'm thinking T-Stat's stuck open. I think it's a 160 degree thermostat, but shouldn't it be running warmer than that? Better than overheating - LOL. But I'm wondering with the engines running that cool will the ecm/pcm sense the cooler temps and compensate with richer fuel mixture causing gas to be used at a greater rate. I'm not the original owner. For all I know the T-stats could be removed. Suggestions? I wouldn't think replacing the stat's would be to difficult. Thanks !
     
  2. Phil S

    Phil S Well-Known Member

    Oct 16, 2020
    Taxachusetts
    2004 300DA
    5.0 Merc MPI
    Bravo III

    2022 KL Tender
    6hp Mercury OB
    I just replaced both thermostats (nothing wrong just regular maintenance) but I haven't run the boat yet to see the warmup temp. I had 160s before and it always ran right around 160-165.

    I guess it's possible that they are stuck open, but for it to be that way on both at the same time, it's more likely the PO removed them. I'm not sure why, since an MPI is designed to operate at a certain temp. Like you're saying, if it's operating all day at 113F then it will be running rich trying to warm up :eek:

    I don't know if it's possible for the sending unit in the thermostat housing (which reads the water temp) to go bad, but unlikely you'd have both go bad and produce the same result in both.

    Swapping out the thermostats -- or just checking to see if they are there -- is easy. Undo the three hoses going to the thermostat housing, undo two connectors, remove two bolts holding it on along with the lifting eye, and the housing comes right off. You just need a new gasket.
     
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  3. Wayward Sun

    Wayward Sun New Member

    29
    May 5, 2022
    280 Sundancer 2004
    Twin 4.3 Alpha Gen 2
    Thanks Phil ! Yes - looks easy enough. Still working on other issues too. Had both lower shift/throttle cables replaced. I can now find neutral and I'm getting better with my slow speed maneuvering. When we pull up to the raft-up I didn't see anyones eye's bulging out of their heads this time - LOL! Biggest Issue I have now is water coming in around steering pins. Both engines need to come out and both transom assy replaced. That's going to hit the pocket book pretty hard. The boat is safe - not much water in the bilge, but I want it fixed.
     
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  4. Jimmy Buoy

    Jimmy Buoy Well-Known Member

    Dec 3, 2008
    Sarnia, Ontario, Canada
    2004 Formula 27PC
    twin 4.3 EFI/Bravo III Dual Prop Drives
    Thanks for posting - I thought I was the only one with both engines not getting up to operating temps. I'll be diving into the thermostat housings this week and see what's up there as well. Also, both my steering pins had to be replaced - did it myself with the JR Marine Kit from Ohio with a LOT of sweat equity for the first one. The second one was done much faster/easier with the experience of the first.

    Made a post describing the process if you're interested.

    http://clubsearay.com/index.php?threads/bravo-3-steering-pin-leak.109696/
     
  5. Wayward Sun

    Wayward Sun New Member

    29
    May 5, 2022
    280 Sundancer 2004
    Twin 4.3 Alpha Gen 2
    Thanks JB. I've seen other posts on the "not removing engines" type solution for this repair. I checked out your thread. Happy that it worked out for you - well done ! I'm going to enjoy the boat the rest of the season and get some other smaller projects done that I can get taken care of during the season and not interrupt my boating time. The local repair shop refuses to repair it using this method. They will only pull engines and replace the transom assy. I just don't have the time to do it myself. The thermostats will be a piece of cake. Be careful when researching for your parts. I've seen where some of the "kits" provide a picture showing the plastic sleeve as being a part of the kit when in reality it is not included. It might be difficult getting that out and it might get broken removing it. I plan on purchasing a couple so I'm covered either way. Cheers !
     
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  6. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx 502 mag
    2005 Baja 242 islander 496
    502 mpi Bravo 1
    496 mag B1
    Replacing the transom assembly because of a leaky steering pin is crazy talk. That's going to be a big dollar fix . What's he going to do with the old TA's?
     
  7. Jimmy Buoy

    Jimmy Buoy Well-Known Member

    Dec 3, 2008
    Sarnia, Ontario, Canada
    2004 Formula 27PC
    twin 4.3 EFI/Bravo III Dual Prop Drives
    I agree that you don't always get what you see on the ads online. I actually ordered two sets of "Quicksilver Thermostat Kits" that look like old stock, but are still in the original plastic containers from FleaBay. Should be better than kits from China!

    Regarding the repair shop's take on the steering pins, I get it. More profit and easier for them with all their equipment, but I hope they are as reasonable as possible with the costs. It's nothing that can't wait till fall. Unfortunately in my area we don't have shops that are consistently competent/trustworthy. Fortunately I have more time for boat projects and it was handy having it parked in my driveway just in front of the garage to pick away at it in the spring. Still took longer than I anticipated! Best of luck with it.
     
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  8. Wayward Sun

    Wayward Sun New Member

    29
    May 5, 2022
    280 Sundancer 2004
    Twin 4.3 Alpha Gen 2
    I would request they be returned to me so that I could sell them and offset the cost a little.
     
    scoflaw likes this.
  9. Jimmy Buoy

    Jimmy Buoy Well-Known Member

    Dec 3, 2008
    Sarnia, Ontario, Canada
    2004 Formula 27PC
    twin 4.3 EFI/Bravo III Dual Prop Drives
    Since I seem to have the same issue with the same engines I thought it would be good to share my progress.

    Took off both thermostat housings to find that all is normal. They're assembled correctly and the thermostats are closed, but will open once place in 160 degree + water. They close once taken out of the water. Not the issue.

    Saw these two videos from a couple of years ago with a similar issue (posted it today on my thread re my issue) and it turns out that the problem in their case was caused by a cracked water circulation pump brass impeller that would not spin with the pulley. No spin, no pulling in recirculation water into the engine - instead the water flow is forced to reverse. Cooling water is being forced from the pump up from the bottom hose, past the y connection where it can go to the engine circulation pump or to the thermostat housing and continues upward to the thermostat housing. From there it can go underneath the thermostat (side with the spring showing) and directly into the engine. There it provides ambient water temps into the engine and forces it out the engine circulation pump hose effectively filling the engine constantly with raw water from the raw water pump.

    I can't wrap my head around something so rare happening to both my engines at the same time - and now both of your engines too. Not likely. Still, may check it out tomorrow on at least one engine. Not much to lose at this point. Not going to drive the boat as is...
     
  10. Wayward Sun

    Wayward Sun New Member

    29
    May 5, 2022
    280 Sundancer 2004
    Twin 4.3 Alpha Gen 2
    Jimmy,

    I found your post. I have alpha drives, not sure if that makes a difference. Thanks for the follow up. Interested in finding out what you find.
     
    Last edited: Jul 5, 2022
  11. SKybolt

    SKybolt Well-Known Member GOLD Sponsor

    Nov 11, 2014
    Kent Narrows, MD
    1988 460 EC
    Detroit 6v92TA
    (Low profile's)
    Alison Gears
    Westerbeke
    12.5kw Genset
    There are two water pumps on a single gas engine. A circulating pump the circulates the water/anti-freeze within the engine and a raw water pump that pass raw water (sea/lake water) through the heat exchanger. If your engines are "Fresh" water cooled as it is called, meaning anti-freeze circulates with in the engine, then your thermostat is most likely 160 degrees, if it is water cooled, no antifreeze or heat exchanger then the thermostat is most likely 145 deg.

    Over what period of time and condition, meaning running the boat at speed or just at the dock, does the temp only get to 113 deg? If your stat is stuck open over time at running at cruise your temp will rise and could actually over heat.

    In your case the raw water pump in on the out drive and the circulating pump is on the front of the engine, where there would be a fan on older cars.
     
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  12. Wayward Sun

    Wayward Sun New Member

    29
    May 5, 2022
    280 Sundancer 2004
    Twin 4.3 Alpha Gen 2
    I've only owned the boat since april and only had it on the water twice. I've had a full tank of gas, holding tank full of water - 30 gallons, 85 degree day, lake temp 83 degrees with 4 adults and a kid. When I initially pulled the boat off the trailer and launched - engines were running for maybe 3 minutes while still on the trailer the temp was right at 105 according to the gauges - both analog and digital. putting around the no wake zone @ 750 ~ 800 rpm waiting to pick my son up after he parks the truck/trailer it jumped up to 109 degrees. We were idling for quiet a while probably 15 minutes by the time I picked him up. Another 15 minutes of idle speed to get out of the no wake zone and out into the main channel of the lake - no change in temp sill 109. Rev'd both engines to 4000 and got up on plane. Ran boat for a long way @ 25 mph according to GPS temp never got above 113. It was the same throughout the whole day driving around the lake and going in and out of coves with no wake zones. I was actually in the bilge right after a long run and tying up with our group to flip a breaker on the generator and I could tell that the engines are not up to temp. There was hardly any heat radiating off of them. My 2010 Crownline with 350 mag bravo 3 would have been hot enough to make a grill cheese on it. Something is not right. It's concerning because Jimmy Bouy has the same problem (as far as we can tell) but he pulled the thermo's to day and they seem to be working just fine. Thank you for your interest in my issue! I'll take all the help I can get. LOL.

    My 4.3 Alpha's are not cooled by antifreeze - no heat exchanger etc. Just uses lake water to cool the engine and risers.
     
  13. SKybolt

    SKybolt Well-Known Member GOLD Sponsor

    Nov 11, 2014
    Kent Narrows, MD
    1988 460 EC
    Detroit 6v92TA
    (Low profile's)
    Alison Gears
    Westerbeke
    12.5kw Genset
    So both engines are acting the exact same way? I am going with the PO removed the thermostats from the engines. Replacing them will probably reveal why he removed them. If that is not the case then I would have to look at the engines and situation to understand it better.
     
  14. Wayward Sun

    Wayward Sun New Member

    29
    May 5, 2022
    280 Sundancer 2004
    Twin 4.3 Alpha Gen 2
    Skybolt - thanks When I get a chance I'll pull one and see what it reveals.
     
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