Yet Another Overheat Question

[TX Duck Guy]

I've been searching the posts and I haven't found quite what I'm looking for. So here goes:<br /><br />I have a 1963 Evinrude 40hp selectric shift (model# 40373db)<br /><br />Took it to the lake yesterday and started it for the first time after my 'overhaul'....ran great.<br /><br />I specifically looked for a pee stream or telltale and did not see one. The aft hole just under the cowl kinda spit some water. After a while I noticed the overheat alarm was going off.<br /><br />New impeller, new t-stat, all lines and passages checked for blockages-none found. I had the lower unit off two days ago to check the water pump, looked OK. <br /><br />Should my engine have a stream coming out at all times? <br /><br />How do I troubleshoot this? My manual isn't so good on the cooling system part.<br /><br />Six days until duck season and I'm going insane trying to get it fixed!!!<br /><br />Thanks in advance!

 

[rodbolt]

Re: Yet Another Overheat Question

hello<br /> is the pressure relief spring and valve in place?<br /> the other problems we had were corrosion building up in the corners of the wear plate pocket and not allowing the wear plate to seat and it will suck air. the next is the pot metal housings wear badly. always replace them. the third in the salt pond is the grommet in the head adapter will be dislodged or crushed by corrosion.<br /> check the simple stuff first.<br /> good luck and keep posting

 

[TX Duck Guy]

Re: Yet Another Overheat Question

Yes, the spring with the plastic plug, cup and seal are present in the t-stat housing. I installed the plastic plug pointing up (towards the bottom of the t-stat), like the pisture in the manual.<br /><br />Of anything I looked at, the pump housing looked as though it had the most wear. I will try to find a new housing and wear plate.<br /><br />Should this motor have a 'pee stream' at all times when running? Mine only dribbled and spit water.

 

[Solittle]

Re: Yet Another Overheat Question

At low rpm the exhaust relief hole below the rear cowl will spit. That is normal. As you increase rpm in the water the flow will go from spitting to a steady stream. I don't think your motor has a "pisser". I think you are on the right track with the water pump.

 

[TX Duck Guy]

Re: Yet Another Overheat Question

That was what I really wanted to know. I'm going to try and find a 'new'' water pump, plate and temp sending unit. I'm not trying to just throw parts at it, but whatever I can do to get it right, I'll do!<br /><br />Thanks Much!<br /><br />Brandon

 

[lark2004]

Re: Yet Another Overheat Question

does your water pump have two pipes going up to the powerhead?<br />My selectric shift does and one of those is the water outlet, so you won't see a steady stream at any time(maybe fit a water presure gauge). The hole under the cowl is the exaust relief, some water will spit out of it, but never very much. Check for blockages in all the water galleries if it is genuinely overheating.

 

[TX Duck Guy]

Re: Yet Another Overheat Question

Lark,<br />Yes my motor has two tubes running up to the powerhead. It acts just as you mention. I'm going to replace the water pumpm and wear plate soon as a precaution...just in case. <br /><br />I am suspecting a bad sending unit. The alarm that I installed is LOUD. When it went off theis past weekend it was very soft. So, that has me suspecting that the sending unit (probably original to the motor) is leaking a little voltage and causing the alarm to go off prematurely.<br /><br />When we got it on the trailer, we pulled the cowl and were able to touch the powerhead bare handed without a problem, so I don't think it was really overheating. Also, the hot water choke on the carb worked just fine which makes me think I had good water flow through the head. <br /><br />So, I'll replace these parts and see what happens!<br /><br />Thanks Much!<br />Brandon

 

[lark2004]

Re: Yet Another Overheat Question

I am fitting an electronic thermometer to my engine, the sensor is potted into the same position as the original temp sender. I will be able to set the temperature alarm on the thermometer at whatever temp I want. And be able to monitor the temp all the time too.

 

[qapd]

Re: Yet Another Overheat Question

Lark2004<br /><br />Can I ask where you located such a thermometer. I am interested in one for a 98 150 Johnson.<br /><br />Thanks,<br />qapd<br />'97 Mako 191

 

[TX Duck Guy]

Re: Yet Another Overheat Question

That sounds really interesting. I'd like to try something like that myself... Is this an automotive temp sensor/alarm or is it a marine one?

 

[lark2004]

Re: Yet Another Overheat Question

It's a kit that I bought from **** Smith here in australia. Try looking in Radio Shack. No it isn't specificaly marine, but I am making sure that I build it into a watertight enclosure. If you are handy with electronics, there are a few websites that have schematics for basic digital thermometers, try doing a google search for thermometer schematics.<br />Good luck!

 

[lark2004]

Re: Yet Another Overheat Question

Ok aparently I can't put the stores real name on the post, the first half of the name is being censored, it's initials are DSE. here is their web site: www.dse.com.au you'll see what I mean.