3.0 merc on a hose gets warmer than I want

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
The unit should run cooler on a hose not warmer, did you get the water tube in OK sometimes if not lubed they will turn a grommet on it's side and restrict water flow, ck the supply hose in the gimbal hsg. for leaks, might have a bad therostat
 

tommays

Admiral
Joined
Jul 4, 2004
Messages
6,768
Re: 3.0 merc on a hose gets warmer than I want

well the first thing that comes to mind is how much of the old pump and gaskets did you reuse??<br /><br />the second would be that something did not get put back toghter right<br /><br />and the third would be low water flow due to to something blocking the water flow betwen the pump and the motor that would need to back flushed out<br /><br /><br />the stat makes a great filter and will block water flow also<br /><br /><br />tommays
 

supercub

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Joined
May 6, 2005
Messages
2
3.0 merc on a hose gets warmer than I want

I just changed the impeller on a 89 3.0 inline merc with a gen 1 alpha one. When running on a hose I seem to be getting into the 160-170 range in about four to five minutes. The reason I am shaking my head at this is that BEFORE CHANGING the impeller it ran cool on the hose. Is this normal? If so what caused the change. The impeller, pre replacement, had a few cracks and one blade was about 3/4 torn off. The new impeller made it harder to turn the drive shaft while in gear, lower unit off the boat. Any imput and education on this matter is valuable to me. PS water is comming out of both exit ports with the new impeller and would only rarely spurt out of the port side exit with the old one. This is my first I/O :)
 

supercub

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Joined
May 6, 2005
Messages
2
Re: 3.0 merc on a hose gets warmer than I want

Mr Mays is right. Thank you both very much for input into my problem. On to the solution. I lowered the lower end and greased the waterpipe, used about 4-5 pounds of compressed air and blew up through the copper waterpipe and blew out the system-to the engine pump. Reassembled and used a better hose, more volume and pressure. Engine ran cool and smooth. I don't know what exactly fixed it but I'm water bound today. Will use both hose when flusshing to isolate that issue. Thanks again fellas<br />ps I used none of the old impeller components including new base, pump, gaskets, pump hosing, etc. also changed lower end grease.
 

Bondo

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Joined
Apr 17, 2002
Messages
71,082
Re: 3.0 merc on a hose gets warmer than I want

had a few cracks and one blade was about 3/4 torn off.
Did you find All of the Missing Piece ???????<br /><br />If you Didn't,...... I suspect your problem will return,.... Till You Find It........
 
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