OMC Overheating at idle speed only.

[cimy3]

Help. 1984 OMC 3.0L overheats at idle, but not at cruising or high speed. At these (higher)speeds, temp. runs normally.<br /><br />Any suggestions?<br /><br /> **EDIT**<br /><br />items replaced:<br /> thermostat<br /> belt

 

[Bondo]

Re: OMC Overheating at idle speed only.

You need a New Impeller(raw water pump)......

 

[bolo789]

Re: OMC Overheating at idle speed only.

outdrive impeller is going bad

 

[cimy3]

Re: OMC Overheating at idle speed only.

bondo & bolo789...thanks for the feedback. <br /><br />How difficult is the process of replacing it?

 

[karayj]

Re: OMC Overheating at idle speed only.

bondo sounds right hey always is but what are you calling over heating 180 200 220??? my boat at 800 rpm heats up to 190 at the at 1,000 rpms it cools to 160 so i may have the same problem

 

[cimy3]

Re: OMC Overheating at idle speed only.

It hits 220 easily. At that point I increase speed to keep heat from rising.

 

[Striper Blues]

Re: OMC Overheating at idle speed only.

replacing the impeller is a piece of cake and only cost about 20 bucks with new seal. You have to remove the housing on the aft side of upper unit. On my 3.0L omc its held on by three small bolts. Once you have the housing off the rubber finned impeller just lifts off the shaft that drives it.

 

[cimy3]

Re: OMC Overheating at idle speed only.

Pbburke....thanks. I will tackle it soon. With OMC are all the impellers the same? <br /><br />What is the serial (?) number for a replacement? <br /><br />If I can't get it local, does anyone have any suggestions on where I can get one?<br />THANKS!

 

[Striper Blues]

Re: OMC Overheating at idle speed only.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2486559274&category=26455

 

[Lou C]

Re: OMC Overheating at idle speed only.

I think he is talking about a Cobra (86-93), yours is probably a stringer drive (big rubber boot around the transom). Check on <br />www.dougrussell.com for assembly diagrams.

 

[BinLurkin]

Re: OMC Overheating at idle speed only.

Mine does this too. I pulled the raw water impeller & it looks good. Should I have replaced it anyway? Sounds like it? It don't overheat, just runs on the hot side of normal.

 

[Striper Blues]

Re: OMC Overheating at idle speed only.

I have had my outdrive rebuilt with new impeller housin, plate etc and it still didn't bleed right, meaning very little water was getting pulled up. You can check by disconnecting the hose at the thermostat housing after the engine is running with the outdrive submerged in water not on the ear muffs, they "force" water and you want to see if the impeller can pull it. If its working properly you will get a full strong stream the size of the hose. I tried changing just the impeller and no luck until I changed the housing and plate as well. This lesson cost me $850 in blown head gasket, spend the fifty bucks and put a new kit on it.

 

[danthern]

Re: OMC Overheating at idle speed only.

if yours is a stringer and not a cobra, it's not a piece of cake. Most sources (Clymer Manual) say to pull the outdrive. I was able to change mine without completely pulling the whole drive, but it was a pain in the you know what. Hope it's a cobra

 

[danthern]

Re: OMC Overheating at idle speed only.

if yours is a stringer and not a cobra, it's not a piece of cake. Most sources (Clymer Manual) say to pull the outdrive. I was able to change mine without completely pulling the whole drive, but it was a pain in the you know what. Hope it's a cobra