1975 9.9 Water problem

elong · Dec 11, 2010

I just got a 1975 9.9 evinrude that has set a year or so. I am not familiar with this engine. Starts and runs good but when running with ear clamp over water intake ports I am not getting any water coming out of pee hole... I have not run more than a couple minutes at a time to avoid overheating. Does this engine have a thermostat that has to open before water will circulate? Is there an easy way to check for proper water pump operation / blockage without removing lower unit?

jasper60103 · Dec 12, 2010

Re: 1975 9.9 Water problem

elong said:
I just got a 1975 9.9 evinrude that has set a year or so. I am not familiar with this engine. Starts and runs good but when running with ear clamp over water intake ports I am not getting any water coming out of pee hole... I have not run more than a couple minutes at a time to avoid overheating. Does this engine have a thermostat that has to open before water will circulate? Is there an easy way to check for proper water pump operation / blockage without removing lower unit?

I always check my water pump by running the motor in a deep barrel of water. If that doesn't work, I would give the water pump test a try. See video...
http://www.youtube.com/watch?v=xAJfBKNs7bo

bktheking · Dec 12, 2010

Re: 1975 9.9 Water problem

Probably blocked up, run some weedeater line up through and try and clean it out. Some times it's blocked up in the fitting which means you have to remove the tube from the fitting and clean it out (the fitting). The motor does have a thermostat however the telltale is before it. Remember it's a water pump indicator and doesn't mean that the rest of the system is functioning. If there is any suspicion that the stat might be a problem replace it or you will overheat/underheat the motor.

The other issue these motors had was the grommet at the top of the water tube in the exhaust housing. Over time they collapse/deteriorate causing water flow issues.

Is this a fresh or salt water motor?

kbait · Dec 12, 2010

Re: 1975 9.9 Water problem

That model doesn't have a 'pee' indicator. Water will mist out the exhaust port above the waterline after the thermostat opens. My '75 won't mist a drop on muffs, but still cools. When run in a barrel, or lake, it mists out the port at idle (once warm), and pours out at speed (new impeller). Run it in a barrel at the slowest idle possible, and feel a spark plug base. If you can put your fingers on it for 2 seconds, you're good. If you splash water there and it boils, investigate further (likely worn impeller.) Good luck!

bktheking · Dec 12, 2010

Re: 1975 9.9 Water problem

That will teach me to post when I wake up LOL. Yup , I keep thinking about my 76 that I installed one on.

elong · Dec 12, 2010

Re: 1975 9.9 Water problem

This is a freshwater engine, I had noticed that in general it was the salt water engines that seem to have the problem of the grommet collapsing.

If I want to run in a barrel at slow idle to verify thermostat opens and engine temp regulates properly.... if I get high tech and check spark plug base with temp gun, what temp range is going to be norm and when should I shut it down? (I dont know what temp the thermostat is in this one.)

elong · Dec 12, 2010

Re: 1975 9.9 Water problem

ps. I have a manual ordered and on the way.... I know I have time until fishing season really hits here (mississippi) but I just have to know I am ready!

bktheking · Dec 12, 2010

Re: 1975 9.9 Water problem

Mine never goes above 135F

jmendoza · Dec 16, 2010

Re: 1975 9.9 Water problem

You should be able to put your hand on the block for several seconds before it gets uncomfortable...3-4 seconds. That is around 145F, and test the engine in a trash can full of water (be sure the can has no paper or debris in it). My 1975 only blows out a mist from the exhaust releif hole after a few minutes, this is normal for this year model, it has no tell-tale.

boobie · Dec 16, 2010

Re: 1975 9.9 Water problem

I orginally came from a fresh water area and have seen those upper water tube grommets swell up and restrict water flow. Don't rule it out.

elong · Dec 17, 2010

Re: 1975 9.9 Water problem

I just came in from testing in 50 gal barrel of fresh water. Slight mist after a few seconds and blowing / running out pretty good after several minutes at high idle. Ran about 15 min total and could hold against block 3 seconds no problem. Did start trying to sort of back fire with no load (idling) after got warmed up, not as noticable in gear... seemed to help if run about 1/4 choke.
I tried using the lean/rich knob, did not seem to help.

Will Bark · Dec 17, 2010

Re: 1975 9.9 Water problem

May have sucking up exhaust fumes from the barell; you are running with cowl off aren't you?

elong · Dec 17, 2010

Re: 1975 9.9 Water problem

After shutting down it set for several minutes before starting, so exhaust fumes were not there... yes running with cowl off. I let it idle down and it dies.... starts back up with one pull on about 1/4 choke.... but still sort of miss / pops. I guess carb needs adjustment.

elong · Dec 17, 2010

Re: 1975 9.9 Water problem

what octane gas usually use in this engine?

boobie · Dec 17, 2010

Re: 1975 9.9 Water problem

Sounds like you may need a carb job or the correct adjustment on the low speed needle. The "pops" you hear usually come from to lean an idle mix.

1975 9.9 Water problem

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