Evinrude 1991 Overheated

drmikeb04

Recruit
Joined
Jun 18, 2010
Messages
5
My boat has been runing great, until I went out last night. I was losing speed, and gave more throttle, but the boat continued to slow down, and the motor then shut off. There was lots of smoke. It was dark out, so I got towed home. Today I noticed that both hoses connected to the starbard thermostat cover was melted and disconnected. I was able to pick up a new thermostate cover, then I reconnected the hoses, and when the motor did start, I had to give a lot of gas, because when i came down to idle, it would just shut off. Now it isn't starting anymore, but it turns over. It turns and turns, until it sounds like its going to start but just stops, then the starter wheel comes down and spins like it was started. When i had it running, high, this morning water was coming out of the engine, so i believe the issue is not with the impellar. I believe the motor overheated because I losy the intergrity of the thermostats and the hoses that run between the two cylinders. Anything on the damage caused bye overheating, and possible diagnosis of my situation would be greately appreciated.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Evinrude 1991 Overheated

recharge the battery. do a compression check, you may have burnt up that bank of cylinders.
 

drmikeb04

Recruit
Joined
Jun 18, 2010
Messages
5
Re: Evinrude 1991 Overheated

Installed two new thermostats with diaphrams, b/c others were blown. Motor starts, but I have to keep idle high, and when I come down on throttle it stalls. I took it for a test ride, after I idled high in neutral, and then quickly put it in forward. Went for a ride, and when I gave it gas, I had about 30-40% of the power I had previously, and before I overheated.

okay, I checked the compression. 1= 70, 2=60, 3=55, 4=50, 5=50, 6=0

Impellar is working, and water comes out, but when I cover the hole, where the water comes out of the motor, water leaks out of the head....the leak is on the head that has the lowest compression.
 

whalerfreak22

Petty Officer 3rd Class
Joined
Jul 16, 2008
Messages
76
Re: Evinrude 1991 Overheated

sorry to say but that motor is headed to evinrude retirement home!its not worth rebuilding that block at all i suggest looking for a parts motor with a good block.good luck!
 

BigB9000

Lieutenant Junior Grade
Joined
Dec 5, 2007
Messages
1,154
Re: Evinrude 1991 Overheated

I almost agree....

But It might be worth changing/checking the head gaskets first.

a V-6 is pretty expensive to replace.
 

drmikeb04

Recruit
Joined
Jun 18, 2010
Messages
5
Re: Evinrude 1991 Overheated

I milled both heads, put in new head gaskets, and now the engine has increased compression, and is running again normal. However I did find that water wasn't coming from the engine, so I am now going to change water pump in lower unit. Thus far, after overheating and melting the thermostats, I changed both thermostats, hoses that connect to each thermostat, milled the heads, and put in new head gaskets. Now I am going to change water pump, and hopefully it will all be like it was before i overheated.
 

drmikeb04

Recruit
Joined
Jun 18, 2010
Messages
5
Re: Evinrude 1991 Overheated

found out that there was no guide to my water pump, so I inserted one, and now the motor is running perfect. I was having trouble going into reverse, but found that the shift shaft from lower unit should be 20.94" on 20" shaft, and add 5" for 25" shaft, done in neutral. I went by those figures, and now the motor is running normal, and I am able to get into reverse w/ no issues. Thanks all for your help.
 
Top