1970 Evinrude 85hp dies at idle

[adogramacian]

Last summer, I convinced my future father-in-law to attempt to get his old Evinrude up and running. He knew we needed a powerpack at the least. Using the manual and help from this website, we changed the powerpack, coil, new plugs, new impeller, and rebuilt one of the carbs (they only had 1 rebuild kit in stock). Cleaned the other carb, and cleaned the points (I think, under the flywheel). Replaced the fuel lines, cleaned the gas tank connector (was all gummed up). We finally get the engine running, which is great, but after running for 25-30 minutes, she stops running and won't start again until she has rested for 15-20 minutes or so. We had the hose hooked up and the water pump must be running because we had rather warm water coming out of the motor. We are at a loss as to what else it could be. He thinks it might be the fact that we are using a new fuel tank instead of the original. Any ideas would be greatly appreciated. Motor is a 85093d, 1970, 85HP Evinrude. Thanks.

 

[OBJ]

Re: 1970 Evinrude 85hp dies at idle

Welcome adogramacian!<br /><br />Think I would get the other carb cleaned/rebuilt first.<br /><br />I have never had the oppurtunity to work on this motor but I would think that the idle needles will need adjusted.....in the water with the boat underway. A turn and a half out from gently seated would seam a good starting point.<br /><br />While your in there, do check your fuel lines. Replace any that have become hard with time.<br /><br />Get a service manual. Will help a lot.<br /><br />Keep in mind that for this ignition system, you will need a top shelf battery..at least a 70 amp hour. This particular ignition system has an amplifier that will self distruct if the battery voltage goes to low.

 

[BoatBuoy]

Re: 1970 Evinrude 85hp dies at idle

Even though it's putting out warm water, check the engine temp when this occurs by placing your fingers on the head. You should be able to leave them there for a second or two. Any hotter and you've got cooling problems. Your symptoms are classic for over-heating.<br /><br />Are you sure the gas tank is vented? That would cause something like you're experiencing also.

 

[OBJ]

Re: 1970 Evinrude 85hp dies at idle

Take a look at the link below and click on engine diagrams. Follow the prompts. You can find the parts breakdown of your engine. <br /><br />If the engine has set for a while, replacing the water pump would be a good idea. If it seems to be pumping and it gets hot as outlined by BoatBuoy, you could have problems with the vernatherm (fancy name for thermostat)like being stuck closed.<br /><br />Here's the link.<br /><br /> http://www.evinrude.com/en-US/

 

[adogramacian]

Re: 1970 Evinrude 85hp dies at idle

Thanks for all the suggestions. I didn't realize Evinrude had the breakout of parts available online; I could've sworn I looked on their site for it last summer and didn't find anything. <br />I forgot to mention something in my original post. After running for its 25 minutes or so, the area around the sparkplugs was not too hot, but the flywheel was nearly untouchable. Is that normal? I thought if anything, the area where combustion takes place would be the warmest.<br /><br />Also, the two round holes in the back of the motor never had more than a sprinkling of water shooting out. Is water supposed to come out of there?<br />Thanks again!

 

[adogramacian]

Re: 1970 Evinrude 85hp dies at idle

OBJ, I used the Seloc manual, but don't remember reading about the vernatherm. After pouring over the the breakout of the "Exhaust Cover Group", I have found the location of the vernatherm. My fiance just sent me a picture from last summer of the engine, and I think I found the Thermostat Housing. If I am correct, it is located directly under the powerpack. I put a picture on a website; I circled what I think is the vernatherm. (Yes, the powerpack looks real bad. These are pre-upgrade pictures!)<br /><br /> http://www.conifercompanies.com/images/vernatherm.jpg