82 model 200 cooling problems

[drummer0901]

First of all, thanks for all the help everyone gives on this board. I am sure my local dealer would be very tired of me by now.<br /><br />First of all, I am very new to boating, but have mechanical sense, at least I think.<br /><br />I have a 93 Procraft Super 180 that I thought had a 93 or so Black Max 175. After trying to order some parts with my serial number(s), I realize now that I have an 82 200 Powerhead, and an 84 200 Midshaft. This boat sat up for a year. When I bought it, it ran very well, for about 30 minute test run. Over the last month, every time I go out, it begins to overhear (constant beep), so after reading here, I decided to change the impeller. The local dealer didn't have the water pump kit so I went to NAPA, order the part and had it next day. I installed the water pump kit (new housing and everything) Installed the lower unit, had some shifting issues, but thanks to iboats, everything is fine. So I get my $30 set of muffs because of the low water pickup in the mail today and I check to see if my water pump works. Nothing out the pee hole, so I think, maybe thermastats have to open. I let the temperature guage start to climb, then shut her down. So my mechanical sense, says to check the thermastats to see if they are closed, after removing the covers, there are NO thermestats on either side. So, me thinks, removed lower unit to see if water pump install is still okay. The rubber grommet over the top housing is chewed up and the impellar is stuck on the driveshaft. The lower half of the housing in the NAPA kit is slightly different than the one already in the motor. The NAPA lower half was one solid piece, and the other was 2 pieces. My frustration keeps getting worse. Now after 4 hours of careful cutting, prying and all, the impellar is off. I want to make this motor right. I assume there should be thermostats? Did I possibly get the wrong water pump kit? why would the top of the housing get chewed up? Why would the impellar get stuck? Could it be possible that my 82 powerhead/84 mid-section have a different year lower unit that needs a different water pump? <br /><br />Last but not least, Mercury Parts Express has the same part number for 2 different reference numbers on the diagram. I assume this motor only has 2 thermos, 1 on each side?<br /><br />Thanks for any and all help

 

[KCLOST]

Re: 82 model 200 cooling problems

Yep, two thermos, <br /><br />And always get the proper kit from a good marine dealer... <br /><br />You should have no problem if you get the proper one... <br /><br />I would also check the pressure relief valve on that motor.. That can cause overheat conditions, depending on what type of problem it has, at both lower and higher rpms....<br /><br />Let us know...

 

[drummer0901]

Re: 82 model 200 cooling problems

Where is the pressure relief valve? I have ordered the merc service manual but have not received it yet. Under what heading would it be on Mercury parts express? Is it easy to check or should I just go ahead and replace it?<br /><br />Thanks KCLOST

 

[drummer0901]

Re: 82 model 200 cooling problems

I think I found the relief valve. Took it off and a little bit of sand fell out. I ran some water over it to clean it. Do I need to rebuild this valve? <br />Why doesn't the part number stamped on the cover match up with Mercury's number?

 

[KCLOST]

Re: 82 model 200 cooling problems

It is always good to replace the poppet valve assembly every other year. Since you have it out. I would replace the diaphram, spring, grommet and carrier, and of course the gaskets for the cover plates... You will need to pull the assembly out completely by the way and clean the hole in the block that it fits into. The grommet and carrier are fitted to the hole in the block and you will need some small fingers or needle nose plyers to get them out.<br /><br />If it was stuck open (not closing) at lower rmps the water will be dumped out of the block and you will overheat at idle or no-wake speeds. It is designed to only open at rpm levels above 3000 so more water flow is allowed to circulate the block.

 

[KCLOST]

Re: 82 model 200 cooling problems

Just to make sure you found it, it is located on the starboard side of the block below the switchboxes, down low..<br /><br />Here is a schematic of possible designs you have, pretty straight forward..<br /><br /> Poppet Valve

 

[drummer0901]

Re: 82 model 200 cooling problems

Thanks a bunch<br /><br />I have the valve apart and parts ordered. Is there anything else that could go wrong with the cooling system? Why would the previous owner remove the thermos?

 

[andy6374]

Re: 82 model 200 cooling problems

Originally posted by drummer0901:<br /> Why would the previous owner remove the thermos?

Probably because he thought the engine would run cooler and better. Cooler Yes, better NO!<br /><br />For the most part if the waterpump, poppet assembly, and tstats are changed out every 2 seasons you don't have to worry about the cooling system at all.<br /><br />Other small things that pop into the cooling equation that occur less frequently:<br />-Blown or leaking head gasket<br />-The grommet and seal at the top of the midsection where the water tube enters. The grommet can swell and corrode and inhibit good water flow.<br />-Lean carbs can heat things up. I suggest cleaning these every 3-4 seasons as well. Lean condition induced by an ailing fuel pump as well.

 

[KCLOST]

Re: 82 model 200 cooling problems

Ok, <br /><br />Good to hear...<br />After you get the proper water pump kit, with new impeller, housing, gasket, and base plate intalled and all the bolts nuts torqued down properly,<br />and<br />after you get the pressure relief valve parts intalled,<br />and<br />after you install new thermostats...<br /><br />This is what you should see...<br /><br />When you run the motor on the muffs, run the hose so you still see some water exiting around the muffs while the engine is running. You shouldn't have to run the hose full blast at all. We don't want to over pressurize the cooling system for testing purposes, But we want to make sure that you are providing enough water that the pump has the ability to move up to the block. <br /><br />Now at idle and and after about 10 seconds of running, the block will fill with water and you should see a pretty weak stream or weak spurts of water exiting the tell-tail.<br />The engine will start to heat up, and "if", and that's a big "if", your engine heats up the water to 145F the thermostats will open or start to open. At that point you will see the tell tail stream increase to a nice steady strong level. It's very possible that your engine with your water from the hose will not heat up enough to let that happen. You can increase the rpm a little but don't go above 1500 rpms while using the muffs.<br /><br />At idle with the stats closed you should see around 10psi of water pressure, with the stats open and at idle it will drop to around 5psi...<br /><br />Let us know...

 

[drummer0901]

Re: 82 model 200 cooling problems

After pulling everything apart, I realize now that the $30 muffs that are supposed to fit my low water pickup will need to be modified to fit snug enough for accurate water pressure. Me thinks I might go to the lake to test when all the parts arrive. I worry that I might have overheated the engine and done damage during my last test. I only ran for a few minutes, temp gauge hit about 120 and I shut it down. In all my parts order, I also got a compression gauge and will check compression when it comes in. It seems I got the shaft on buying this boat, but I guess you live and learn.<br /><br />Thanks for all the help guys!!!!

 

[KCLOST]

Re: 82 model 200 cooling problems

Low water pickup????<br /><br />You don't have the standard intakes on the sides?<br /><br />I guess I missed that, yea, you want to make sure you have the proper set of muffs...

 

[drummer0901]

Re: 82 model 200 cooling problems

I have the correct muffs, but they don't fit seal, I guess it is hacksaw time!!!

 

[andy6374]

Re: 82 model 200 cooling problems

Put it in a barrel and report back!