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Thermostat housing, Tstat and gaskets, i have questions.

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  • holorinhal
    started a topic Thermostat housing, Tstat and gaskets, i have questions.

    Thermostat housing, Tstat and gaskets, i have questions.

    i have a 1981 Merc 260( 5.7l 350cid) with a MC1 or Alpha drive. I upgraded fron the old cast iorn log exhaust to EMI Thunder center rise exhaust. i aslso changed the thermostat housing to a Sierra #18-3530-1.

    i originally hooked every thing up , without a tstat to get the engine fired up, but the water temp was rising pretty quickly to above 200*.

    I purchased a Tstat kit from the local marine shop. At first they gave me a 160* kit # 807252Q5 and it had a regular gasket for the intake to tstat housung fit. i ased them to give me the 140* kit, #807252Q4, because every thing i have read said that the 260 needs the 140 and that is what was in it before. the only difference is that the gasket in the 140 kit has two small holes on each side, of the bolt hole.

    So my question is, before i install the $50 kit, is do i have the right one? What are the small holes in the gasket for, should i use the 140* or the 160* tstat?

    Here is a pic of My set up.


  • Fun Times
    replied
    Originally posted by holorinhal View Post
    Just s little update. I found the correct T/stat house on eBay, for $50.
    Good to hear you found one at a reasonable price. Even if you don't notice a change, at least you know you're setting up your engine correctly to specifications.

    I had replaced all gauges with Autometer marine gauges, but didn't change the temp sender. I bought an autometer temp sender and swapped it out?
    To see the complete version of the copy and paste seen below which include all the graphs and charts available, all the ***'s in the links are james town distributors .com as one word.
    http://www.james towndistributors.com/userportal/document.do?docId=842

    Water Temperature System Accuracy?
    [IMG]http://www.**************************/userportal/woeimages/howtos/adobe.gif[/IMG]
    Temperature systems used on boats and other vehicles give a general indication of the temperature in which the sender is operating. We use the term "general" as the system can vary to a maximum 15 degrees from actual temperature.


    [IMG]http://www.**************************/userportal/woeimages/howtos/842a.jpg[/IMG]

    [IMG]http://www.**************************/userportal/woeimages/howtos/842b.jpg[/IMG] The gauge itself is accurate to within about 5 degrees at the mid-scale position. The sender is accurate to within 10 degrees at 200 degrees (as are competitive units). The sender tolerances widen as temperatures become higher or lower than 200 degrees. (cont'd. on next page)
    Although sender/gauge tolerances rarely run to the maximums (at the same time), the system can possibly indicate up to 15 degrees difference from actual temperature at 200 degrees. These specifications are developed at a system voltage of 14 volts. The sender is also susceptible to "self heating" when electrical current passes through the sender. The self heating causes the sender to become warmer than the actual temperature of the fluid (the gauge is compensated for this effect at 14 volts). If the system voltage is varied to 13 or 15 volts the gauge may read 5 to 6 degrees higher also.
    In a few cases it is necessary to put a temperature sender and a temperature switch (to operate a light or buzzer) in the only engine opening. In this case a "tee" is used. However, when the sender (or switch) is moved away from the water flow, the water around the sender bulb tends to run cooler. The gauge will also show a cooler reading than the actual water temperature inside the engine. Use of "extenders" or "tees" is generally not recommended.
    [IMG]http://www.**************************/userportal/woeimages/howtos/842c.jpg[/IMG]

    Water & Oil Temperature Sender Identification Guide

    Use this chart for field identification of Teleflex water temperature senders. (ID code stamped on wrench hex of sender. See illustration at left of chart.)

    [IMG]http://www.**************************/userportal/woeimages/howtos/842e.jpg[/IMG]

    Water Temperature System (Inboards & Stern Drives)

    1. To test gauge, voltage from "I" to "G" terminals must be 10-16 VDC. No wire on "S" terminal. Gauge pointer should rest below 120. Next, connect the "S" terminal to the "G" terminal (leave "I" and "G" terminals connected). The gauge pointer should rest above 240.
    2. The resistance of the sender can be measured to determine the sender's correct operation. Remove wire to gauge. Connect an ohmmeter to terminal of sender and to engine block. Approximate values are: 75 (room temperature) = 600 to 800 ohms; 212 degrees = 55 ohms. (These are single station values- twin station values would be 1/2 these numbers).
    3. If sender is shorted (0 ohms) gauge will read above 240F.
    4. If sender has infinite resistance (Open) gauge will read below 120F.
    5. If the gauge reads lower than expected, was sealer used on the sender threads? (See illustration.)
    6. The accuracy of the system (gauge, sender, voltage range) can vary as much as 16 degrees at 180F.
    7. Use of pipe extenders to plumb both a sender and temperature switch (for horn or warning light) from one port is not recommended. The amount of weight extended on the fitting of a vibrating engine could cause fatigue-related breakage. Also, the sender is removed from water flow inside the engine and will probably read cooler.
    8. Teleflex does not offer senders for metric threaded ports.
    9. Dual Station installations:
      • When replacing one gauge in a two station installation, the second gauge may need to be replaced as well.
      • Mixing two gauges from different manufacturers to one sender may cause an error in both gauges.
      • If one gauge fails the second gauge will read much higher than expected.
      • If sender fails "open", both gauges will read below 120F.
      • If sender fails "short", both gauges will read above 240 degrees.
    10. Twin engines: It may be helpful in troubleshooting to switch either the senders or the gauges from engine to engine.



    [IMG]http://www.**************************/userportal/woeimages/howtos/842d.jpg[/IMG]

    Water Temperature Monitoring- Outboards

    1. The temperature monitoring kit includes all parts to adapt to any of the situations noted above. Yamaha engines will require an adapter P/N 61886P in addition to the kit.
    2. Outboard engines use raw water for cooling and are mostly aluminum, so they operate cooler than stern drives. Consult dealer or engine manual to determine maximum operating temperature of your engine.
    3. The sender in the kit has 1/8-27 NPT threads with I.D. Code "10" or "60" stamped on the hex. Senders stamped "230" won't work correctly.
    4. Part number of the sender is 52320S010; the flat bracket is 54552; the Z bracket IA55009.
    5. Some engines include a threaded hole directly into a water line. The temperature sender can be threaded into the hole, using no sealant on the threads. The threads create the electrical ground.
    6. Some engines have a blind threaded hole for a temperature sender that does not enter the water jacket. After applying thermal compound to the hole, thread the sender in snugly, again using no sealer.
    7. Some Mercury engines have a blind hole flanked by two bolts. These are for tightening the flat plate. First place thermal compound in the hole, then drop the aluminum spacer in the hole. Thread sender into bracket over hole until it hits spacer.
    8. The Z bracket installation is used most often as it fits any engine. The Z bracket through hole is held by any one of the engine's cylinder head bolts. The sender is threaded into the bracket's remaining hole down against the cylinder head. Scrape the paint from the head under the sender to get good thermal transfer.
    9. The kit is supplied with one sender. If a sender is desired on each cylinder bank on V type outboards, a double pole ON-ON switch must be used to switch sender input to the gauge. The gauge can not accurately handle two senders at one time.
    10. Testing the gauge for operation: Connect a hot wire to "I" and ground wire to "G". Gauge should read below the C. Next, Short the "S" terminal to "G". The pointer should go above the H. If the pointer sweeps this way, the gauge is fine.
    11. Testing the sender: At room temperature, with no wires on the sender, it should measure approximately. 600-800 ohms on test meter.
    12. Replacement outboard sender IA96035 cannot be used with this gauge. The gauge will read very high. IA96035 is only for pre-1995 Johnson/Evinrude engines with a 50-250F gauge.


    [IMG]http://www.**************************/userportal/woeimages/howtos/842f.jpg[/IMG]

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  • holorinhal
    replied
    Just s little update. I found the correct tstay house on ebay, for $50. While i was waiting on it to get here, i thought anout some thing.
    I had replaced all gauges with Autometer marine gauges, but didnt change the temp sender. I baught an autometer temp sender and swaped it out? Tan the boat on the hose and the temp stayed at a steady 150-155 degrees. I checked all the temps on the engine with a thermal lazer temp reader and all temps were around 130-140 degrees.
    I took the boat and ran it in the lake and the gauge and actual engine temps were consistsnt with running on the hose.
    So maybe the sender was bad or not compatible.
    When the new tsat that has Alpha stamped on top and 860256-c3 on it, i will go ahead and replace it any way.

    Leave a comment:


  • JaCrispy
    replied
    Just wanted to let you know I took the boat out last Sunday and the new cooling system worked fine. It ran around 140 for most of the day and later on got up to 160 and stayed there. I did a bunch of trolling which may have risen the temps a little.

    Leave a comment:


  • holorinhal
    replied
    Haha, I did try restricting the hoses and it did not help, but that was before i realizedthat the belt was not on, duhhh!

    I will try it again this afternoon.

    Thanks for all the hely, guys! I will repost back.

    Leave a comment:


  • JaCrispy
    replied
    HAHA! I just LOL'd!

    Leave a comment:


  • Fun Times
    replied
    Actually we're glad you found the main problem and it's an easy one....No need to be hard on yourself about it though as I get what you were trying to do.

    At one point I almost asked you for a photo of the front of your engine (complete) as I wanted to see your belt routing and water hoses but held off because you didn't have an engine mounted sea water pump....Bravo type setup.

    To run the engine with the power steering hoses disconnect from the steering actuator, you could just get an adapter that fits both hose fitting ends and connect them together so the pump circulates the fluid.

    So i need to find one that has Alpha stamped on the top, to know that i definitely have the right one?
    Yes it will say Alpha on the housing. Like you say a true 180 is to hot....If you have a 160 thermostat then it's not unusual to see as high 170-173 degrees on the gauge though.
    If you keep checking online & ebay every once in awhile you'll eventually find a good deal on either a new or used housing.

    If possible, try my restricting theory mentioned earlier and see if it helps and let us know so we know for sure or not....Either way you'll still want the correct housing though.

    If you have an infrared temperature gun then be sure to test the accuracy of the temp gauge against the actual engine temp and know what the exhaust system is really running at.

    This one here is one that is offered by Dennis Moore and he states that it is for the upgrade on my year to center rise, but i think the a3 a4 modle was designed after this one was.
    Yep you got it.

    Leave a comment:


  • achris
    replied
    We've all done it...

    At least you found it...

    I've made a few like that too...
    Last edited by achris; April 22nd, 2015, 03:18 AM.

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  • holorinhal
    replied
    Holy crap, i am such a dumb f!@%ing, sutupid braindead, A@# wipe!!!!!!!! I am so F@!$ stupid and embarrassed!!!!! but i am man enough to admit my mistake!

    All this time i have been running the engine without the belt on the water pump!!!!! so the water pump has not been turning all this time! Just because i didnt want to turn the power steering pump! I cant belive that i did not catch that, un till now!! What a dumb *** i am!!! I gess that explains why the water was pouring out of the circulating pump neck, at the bottom, duhhhh!!!!!

    So since i put the belt on and ran the engine with the circulating pump doing its job, the temp was staying steady at 180 and not moving. Not sure if the engine was just hot and needed to cool. I will let it cool all the way and see where the temp climbs too and stops at, tomorrow.

    I know that is still a little warm, but better than it was doing. I am running at idle and on the muffs.
    I know i still probobly have the wrong Tstat housing and will look for the right one with the right Mercruiser part number and see if that cures the entire problem.

    Dam i cant belive i am such a dumd ***!! Its all right you all can call me a dumb *** too! I know you guys are thinking it, hahaha!

    Leave a comment:


  • holorinhal
    replied
    The EMI install instructions, shows the check ball type with a Y fitting to run both hoses to the bottom, for a total of 4 hoses. one each side from the tstat cover and one each side from the check ball t, to a Y, then to the bottom of the manifold. I would just rather use the type i have if at all possible for less fitting and hose.

    I will just try to find a take off or reasonably priced A3 modle in a genuine mercruiser part. It is just hard to tell exactly which you are getting, because they lookexactly the same on the outside.
    So i need to find one that has Alpha stamped on the top, to know that i definately have the right one?
    Last edited by holorinhal; April 21st, 2015, 11:46 AM.

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  • holorinhal
    replied
    No, my engine is a 1981.It had the old log exhaust. My thermostat housing was like this one pictuerd.
    This one here is one that is offered by Dennis Moore and he states that it is for the upgrade on my year to center rise, but i think the a3 a4 modle was designed after this one was.
    No i cant return the one i have, because ibaught it a couple of years ago when i baught the exhaust. I am just now getting around to finnishing it.


    Leave a comment:


  • Fun Times
    replied
    Originally posted by holorinhal View Post
    Ok, sorry to be redudant, but i want to be absoloutly clear, before i buy another $300 thermostat housing. The only reason i ask is because both look exactly the same on the outside.
    That's ok I really don't want to spend your money for you if it's truly not needed. Can you try returning the one you have now?

    The best way I know how to describe the main differences between the two housings (numbers A3 - A4) is the exhaust outlet hose sizes on the bravo (A4) is bigger which basically would be letting more water flow out to the exhaust before letting it get into the engine to do it's job. The A3 Alpha holes are smaller in turn holding more water in...Same concept as having the check ball valves to slow the water flow. Also there should be a difference to the bypass hole internal to the T/housing.

    While you have a version of the T/housing design 3, you don't have the correct size T/housing of design 3.
    The second link below may help with the thermostat idea differences even though it's the older design T/housing.
    More reading for you, http://www.justanswer.com/boat/3byi6...ld-system.html
    http://www.marinemechanic.com/site/PAGE260.htm

    Thanks for the photos of the exhaust in post 16 as it helps because had you needed to run hoses to both the manifolds and risers then you would of needed part number 87290A23 with the check balls.> The A3 should work well with the exhaust you have.


    The part # 860256A 3 for Alpha drive, is for or will work with a Alpha 1 or MC1 and is not specifically for an Alpha gen II. I have read that the water pump in the Alpha gen II is different and similar to the Bravo.
    In the SEC article above, the guy had to switch to the check valve type Tstat house, like this one in this picture by Dennis Moore.
    I would rather not have to use the check ball style if possible. The one like i have is much cleaner, with less hose and fittings.
    Thanks for the help.
    The theory is you shouldn't need the check ball setup with the A3 alpha housing due to a smaller opening. According to design 3, it fit's MERCRUISER200 (2 BBL.) GM 305 V-8 1987 MERCRUISER230 (4 BBL.) GM 305 V-8 1987
    MERCRUISER260 GM 350 V-8 1987
    MERCRUISER260 (4 BBL.) GM 305 V-8 1987
    Which was offered with both Bravo and Alpha at that time.

    http://www.mercruiserparts.com/Show_...I+%2D+ALPHA%29

    Here's a test to try next time you run the engine! Try evenly restricting the hoses between the T/housing and exhaust to see if it helps with the over heat at idle.

    https://www.perfprotech.com/blog/tec...d-cooling-tips < The following quote is from the link!
    The standard raw water cooling system operates via a pressure balance. The easiest way to think about these systems is that you have a circuit of coolant being circulated through the engine via the engine circulating pump. There is also a supply pump that introduces cooling water into this circulation loop, depending on the position of the thermostat and amount of coolant being allowed to exit the system.
    One possible "theory" of why the water was flowing out of the circulating pump inlet is since the cooling is pressurized, when you disconnected the lower hose of off the circulating pump, it may have lost some of the pressure... In turn allowing the water that's in the block to be pumped back out vs being pressurized by the pump/s which would send the water flowing back up to the bottom of the thermostat housing through the thermostat (or bypass when cold) then back down to the circulating pump through/via the big hose system...< Just a guess and restricting the exhaust hoses "may" help tell the story about the over heat.

    Did your old T/housing have the check balls?

    Leave a comment:


  • JaCrispy
    replied
    Alpha one drive. The housing is supposed to be a replacement for the stock housing. I didnt find much info from Sierra on the installtion, thats why I asked questions here. Im running a 140 tstat. Maybe askthe manifold manufacturer about what tstat housing to use?
    Last edited by JaCrispy; April 20th, 2015, 05:52 PM.

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  • holorinhal
    replied
    Originally posted by JaCrispy View Post
    I did a conversion to my '88 5.7. I don't run those manifolds though. I've only run it on muffs and it stays just under 160. Besides the different hose configuration, I just made 2 more openings in my riser gaskets to be 4 holes instead of just 2.

    http://forums.iboats.com/forum/engin...t-housing-swap
    My EMI manifolds have passages that are used with the aluminum risers that can be run on these manifolds, but my Stainless risers do not have passages and use a gasket that blocks off the manifold passages and uses a jumper hose to let water pass from the Manifold to the riser.

    What drive do you have, Alpha 1, Alpha gen II or Bravo? From what i have been reading and if understanding right, the drive determins what is the correct Tstat housing? The Tstat housing that you show, Part number 87290A4, is for a Brovo or Bravo/Alpha genII, and am understanding that , that is the one that i have and wont work with my Alpha 1?
    Who would have thought that a Thermostat housing would be so dam complicated?!

    Last edited by holorinhal; April 20th, 2015, 03:43 PM.

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  • JaCrispy
    replied
    I did a conversion to my '88 5.7. I don't run those manifolds though. I've only run it on muffs and it stays just under 160. Besides the different hose configuration, I just made 2 more openings in my riser gaskets to be 4 holes instead of just 2.

    http://forums.iboats.com/forum/engin...t-housing-swap

    Leave a comment:

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