New boater Force 50 cooling issues

[Rob406]

Hey guys I just launched my boat for the first time last weekend and had some overheating issues...It's an 88 Force 50. I popped the lower unit off to inspect the impeller and unfortunately it looked way better than i expected. It does however appear to be dried up and actually has some hairline cracks in it around the key way. It was tough to spin by hand. The seal on top of the housing looked pretty beat up so I'm not sure if that would be a culprit...I then removed the thermostat and although it didn't seem to be stuck, it was very dirty, and so were all the passages I could see. The inside of the lower unit "casing" was covered in oil residue, but when I flushed the fluid (before I took it out last weekend) the old fluid checked out clean. Because I'm new to boating and especially working on outboards I'm unsure what my next step should be. Everything I broke down today looked rough but I don't have enough experience to know what can get cleaned up and what needs to be replaced, etc. Could use some help from the experts on this one!!!

 

[jerryjerry05]

Even though it "looks" go doesn't mean it's good.
Replace it.
Los like a fresh water motor???
Test or replace the thermostat.
The seal looks bad but not really bad enough to leak.
Put it on the shaft and see how much room it has???
Replace the seal anyway.
When you removed the thermos was there any build up or gunk in the cap?
Pics of the inside?
It's possible the lower unit pick up clogged?

 

[Rob406]

Thank you for the response Jerry. I did order the impeller before I dropped the L/U so at least that is on its way. I am having trouble finding the replacement thermostat and other parts online. I wasn't able to get a clear shot of behind the thermostat. Everything looked pretty dirty but I could not see any build up or gunk. In the meantime I'm going to clean everything up as good as possible. I need to know the best way to clean the passages as I'm thinking it must be clogged up good. Is there anything else I can look for?

 

[Rob406]

I just got back in from playing around with the motor a little bit. The t-stat cover was indeed pretty crusty. Also the thermostat "provision" in the head is very crusty. I cleaned the cover with a pick and a wire brush and some air but need to know a safe way to clean the head and also the other water passages. Also there seemed to be a small amount of black silicone on the inside of the t-stat cover. Not sure if it was enough to obstruct water flow-or maybe from disassembly...Is it safe to shoot air/water through the t-stat port? There are two holes. Also up the intake tube. Someone mentioned coat hanger/makeshift snake. Little unsure about that idea...Id like to see what I can jar free but don't water/dust and debris to go where it doesn't belong. Not familiar with the internal plumbing Any insight appreciated thank you everybody

 

[SkiDad]

that impeller is pretty rough actually. so is the seal - i think that is most of your issue.

 

[jerryjerry05]

If you don't see an obvious build up there probably isn't one.
​The only way to do a de-crud is to remove the head and use a ice pick or thin screwey.

Myself, I wouldn't worry about it.

I had some pics of a clogged thermos and a BAD clogged head but Windows 10 won't let me post them now
Your parts aren't bad enough to worry about a head removal.
The impeller came out whole so no worries about a clogged water tube.
Now if you use the hangar it can poke holes in the thin copper tube. and maybe even dislodge the tube.
Yup shooting air or water anywhere is ok as long as the thermo is out.
If the seal on the top of the pump is not touching the shaft then replace it.
Or replace it anyway.

​Compressed air, even at 3psi can blow up a 6K gal. tanker.

 

[Rob406]

Thanks for the responses guys. Jerry my plan is to scrape around the thermostat housing whatever I can see and shoot some air in there, also I might try to hook my garden hose directly to my pickup tube. Air/water will come out exhaust passages? And nothing will find its way into the cylinders??

One more thing. My impeller arrived today and has only 6 blades. The one I removed has 10. The new one is the same size etc and is listed for an 84-94 Force 50 from a seller on E bay. Could someone confirm how many blades an 88 is supposed to have? Does anybody know where I can buy the impeller housing seal and also the t-stat seal?

 

[Rob406]

Thanks for the responses guys. Jerry my plan is to scrape around the thermostat housing whatever I can see and shoot some air in there, also I might try to hook my garden hose directly to my pickup tube. Air/water will come out exhaust passages? And nothing will find its way into the cylinders??

One more thing. My impeller arrived today and has only 6 blades. The one I removed has 10. The new one is the same size etc and is listed for an 84-94 Force 50 from a seller on E bay. Could someone confirm how many blades an 88 is supposed to have? Does anybody know where I can buy the impeller housing seal and also the t-stat seal?


​

 

[jerryjerry05]

6 or 10 is ok.
No nothing should get into the cylinders

F349307 imp seal,F97607 thermos gasket
almost every Mercury dealer should have or e-bay​

 

[wickware]

No Title

1. I tried to add more light to your pics to show conditions.
2. Did you have a poor water flow showing along your indicator when overheating (Buzzer, Gauge Etc)?
3. I was shipped a 6 blade impeller to replace my 10 and c/n see any differences in water flow.

 

[Rob406]

Thanks for the help Jerry I will be stopping at the dealer on my way home tomorrow.

Wickware to answer your question I am assuming I had very little water flow. I fitted it with an aft. buzzer before going out with help from you guys on the site. It went off in the first 10-20 minutes out. I read these motors don't spit a lot of water but after watching a video online I think it should have been spitting a lot more. The head was hot to the touch. I also have a cyl head temp gauge coming and found a barrel to run it in.

The pics are poor quality they make the parts look better than they are. The impeller cover has a small amount of pitting and behind the tstat was pretty brown and crystally....But no obvious blockages that I could see anyway. Hopefully if the dealer has my parts I can get it back together over the weekend and see if I made any progress. Thanks for all the help

 

[jerryjerry05]

Let us know how it operates under load in the water.

 

[Rob406]

Will do. I ordered my parts at the dealer and they should be in Wednesday so maybe next weekend

 

[Rob406]

Hey guys, little update to share:

Cleaned all visible passages with dental pick and small wire brush, Installed impeller, installed water pump seal, cleaned water pump plate, installed new thermostat, gasket and seal, installed stainless hex head screws for thermostat cover....And the result is.....

Gushes water instantly!!! Going to the lake to try her out tomorrow. Ok one last serious question.

On my shift linkage, where it attaches to the shift rod in the lower unit (via a pin with a cotter pin). I wasn't able to find a stainless cotter pin small enough. What I did was omitted the connecting pin (called pin, gear shift rod lower F85372) I omitted this part and used a larger cotter pin to connect the linkage to the shaft. I don't see why that would be an issue but what do you guys think?

I also ordered the sediment gasket bowl and screen for the fuel pump while I was at the dealer. I hesitated to install because the pump seems to work fine and I don't want taking it apart to mess with anything else in the assembly. What do you guys think about that?

 

[jerryjerry05]

Install a filter inline between the carb and the pump..
​G-2 G- 3 G-12 Fram.
Or a water separating filter in the system.

Your not in salt water so a regular cotter pin wouldn't hurt.
Pics of the new setup??

 

[Rob406]

Thanks for all the help Jerry (again) as requested here is a pic of the setup on Little Ossipee Maine..It's a 64 Duratech 15', was an open hull until I added the hood, dash, forward controls, etc. Was in rough shape when I got it (for free) holes and everything, which I filled using 115 mig spool gun/argon gas (welder by trade) Also the motor sits on a jack plate I made (found out motor sat about 5" too low first time I had it out plus incorrect angle) I have the tank all the way up front. I just added a hydrofoil today which seems to help. It's a work in progress but it runs good (with help from you guys) I owned one other boat basically for wheel-and-deal purposes so this I really consider my first, and definitely the first boat I have really done any kind of work on. Also I added a cyl head temp gauge, she runs less than 140 all day long (after new impeller of course). So I indexed my prop today before I went out (feels like its slipping at high throttle) sure enough my marks are 1/2" apart after coming in. Will need prop advice but I will repost in the correct category.