LOWER unit merc 200 94 also overheating

S

shelbydriver

Petty Officer 2nd Class
Joined
Dec 13, 2002
Messages
173
I am running Hot on the merc 200 94 carbbed engine. runs cool at idle but then when running hard it heats up. Already replaced the thermostats, poppet valve, & hoses, and impeller with new pump cap. There is a grove worn on the driveshaft where the rubber large O ring slides down over the waterpump cap. I think it is because there is side to side play in the driveshaft under the waterpump somwhere.. It wore out the hole in the last water pump cap upon inspection.Is there any kind of sleve made for this problem. I hate to buy a new driveshaft. Is there a bearing in there I need to address? Also noted a little play on the prop bearing too. Also had a tiny bit of milkyness in the fluid. gulp. Is that groove going to make it run warm? Thanks in advance. <br />_______
 
B

BF

Lieutenant
Joined
Apr 8, 2003
Messages
1,489
Re: LOWER unit merc 200 94 also overheating

Hiya,<br /><br />You might want to consider pressure testing your lower unit. On mine (a 150 hp V6), the seals below the water pump were bad, and a small amount of water was leaking from the pump into the L.U.. If there is side to side movement in the driveshaft, those seals might have worn out on yours. <br /><br />By the way, I have previously twisted (broke) the driveshaft on my motor, I think the upper driveshaft bearing (the one right below the water pump) wore out/broke/overheated and that's where the driveshaft broke. So, maybe you should consider replacing some bearings before worse things happen. (?) <br /><br />HTH<br /><br />Brent
 
S

shelbydriver

Petty Officer 2nd Class
Joined
Dec 13, 2002
Messages
173
Re: LOWER unit merc 200 94 also overheating

it appears the movement is front to back in the drive shaft. would a new seal stop that and or is it a bearing? not sure anyone? thanks. I am going to find my manual. Also would just a loose seal cause play in the prop? (prop seal) or is that a bearing problem. Do I need special tools for seal replacement?
 
G

gss036

Commander
Joined
Jan 18, 2003
Messages
2,914
Re: LOWER unit merc 200 94 also overheating

I just had a new impeller installed along with the shaft seal. The mechanic said the book calls for disassmbling of the unit to do the job but he did w/o. Said he knew a short cut??<br />He found a small amount of water in the lower unit and did a pressure check to find the leak.
 
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