I bought a 1984 evinrude 70hp outboard. Havent run it in the lake yet. I was going to take it out today so I hooked the muffs on it and fired it up. Sounds good, pees good. Put it in gear then back to neutral, didnt run it much above a fast idle. Then the pee stream starts getting noticably weaker, it didnt stop but was probably half of what it started like. That water coming out got hotter and hotter, at about 8 minutes an alarm goes off. I shut it down, took a few minutes and it stopped. I waited a bit then started it up again with about the same results. The muffs had a good flow of cold water the whole time.
Is this because its on the muffs? Should I put it in the lake and run it a bit near the landing and see what happens? I’ve never had one do this before, the guy I bought it from told me it ran fine but we know how that works.
Any suggestions before I put it in the lake to test or take it to the mechanic will be greatly appreciated!!
I’d suspect a worn water pump impeller first. 2nd I’d suspect the water muff, it’s probably providing water to only one side and you may not be getting enough water. But make sure you have a good impeller.
“I am constantly amazed at the stupidity of the general public.”
~my dad
Equipment:
190cc Sea Pro w/130 Johnson
1- 18 year old ( has decided being with parents isn’t cool)
1 - 15 year old (still does not mind hanging with the 'rents)
1 - wife (The Warden)
quote:2nd I'd suspect the water muff, it's probably providing water to only one side
Huh???
Most muffs only supply one side, the other side of the muff is to close the opposite side of the lower unit off.
Same cavity…
I would check the t-stat and water pump impeller.
I have seen a impeller dissentigrate and leave small pieces of rubber wedged tightly in the tube that carries the cooling water up to the block, thus blocking the flow when the new impeller was installed.
I would suspect the impeller… When the stram got weaker, this was most likely when the t-stat opened creating more area for the water to cover, and with a worn impeller, it most likely couldn’t keep enough pressure to run enough water to keep it cool. Both the impeller and t-stat are fairly cheap to purchase parts wise and fairly easy to replace if you have a little mechanical tallent. Just be carefull of corroded bolts when removing. If you break a bolt, thats where it gets expensive!!
Key West 19’6" CC 115hp Merc
14’ Fast Craft w/ 60hp Merc
Pulled the thermostat cover, the springs flew out of course . . . found them, they are in good condition, the 2 plugs they were holding seem ok and move freely. The thermostat has some white corrosion on it but seems ok, I put it in a pot of water and heated it up, it started opening around 140-145 and at 155 or so it was wide open. I’m guessing its working like it should, new ones are rated at 143 degrees. Could it just be that I should put it in the water and try it out? I really hate to go through the effort of pulling the lower unit off just to check the impeller, it might be easier to pull it to the lake and try it out.
'Sounds like you did not find anything wrong with thermostats and pressure relief valves. Ergo, there is something wrong somewhere else. You may have a perfectly servicable motor. I wouldn’t risk it until I thought I had probably done what was needed to keep her from toasting herself.
Dropping the foot isn’t that hard. Rebuilding the water pump isn’t that hard. If the impeller is suspect, I’d pull the foot and rework it. Kits aren’t expensive. That way, you’ll have a few years of not worrying about it.
Well it was easy enough to get the lower off. Had to use a dremel and a light touch to cut the impeller off though. Now I need to find some of this sealer 1000 the manual says to use for reassembly. Any substitutes recommended? Thanks
Well it was easy enough to get the lower off. Had to use a dremel and a light touch to cut the impeller off though. Now I need to find some of this sealer 1000 the manual says to use for reassembly. Any substitutes recommended? Thanks
Alrighty then, replaced the the water pump impeller and thermostat per the manual. Fired it up on the hose and ran it at slow speed for awhile, no alarms, good flow of water, looking good in that area.
Maybe another issue tho. My tach isnt working so I hooked an older auto tester tach to the motor, showed around 1200 rpm, any lower rpms and it would shut off. It also sounded like it was idling rough. I pulled the bottom spark plug wire off, no difference, put it back and pulled the middle plug wire off, no difference. Put it back on and pulled the top plug wire off, motor shut off. Is it only running on the one cylinder? I put the tach lead on the bottom 2 wires and they both showed around 1200 rpm on the meter. Plugs look ok so I’m not sure where to go
from here but to a mechanic to check it out
I do not know your motor, in particular. But, I have been warned often not to put the motor in gear at all when on the muffs. I don’t know if that’s true with your motor or not.
Also, I’m not sure putting it in gear does you any benefit over being in idle. There’s no load on the motor when it’s not in the water anyhow, so it’s not going to be burning any hotter. Idling, by itself, is often the most tell-tale test for a cooling system. When I was younger (teenager), we had two Evinrudes (25 and 85) and they would both only overheat if they were idling (impellers were worn).
And yes, I think it is possible that your motor is only hitting one cylinder. I know my own two-cylinder will actually sound just fine (at high idle) on one cylinder, you just won’t go anywhere in a hurry.
Test your spark jump. You can buy a spark gap tester at Parks for $5. You should be getting a solid 3/8 to 1/2" jump on your spark. Bright blue.
“Sire, it belongs in truth to the Church of God, in whose name I speak, to endure blows and not to inflict them. But it will also please your Majesty to remember that she is an anvil that has worn out many hammers.”…Theodore Beza
Sounds like seized piston rings from sitting for a while? Try this de-carb tactic next:
Decarb ; Chances are good if the motor has set for any length of time and you may not know anything about it, that the rings may have become stuck in the piston. This can hamper the running of the motor because of lower compression. The easiest way to help here would be to purchase a commercial de-carbonizing liquid that is ran thru the gas and / or squirted into the pistons, let set, then run it. One that is usually available at automotive parts stores is SeaFoam. This stuff softens the carbon buildup and when the motor is then ran it blows this now softened carbon out the exhaust and many times gives the motor a new lease on life.
One method of decarbing used by many is to mix a strong mixture of SeaFoam into a 1 quart to a 1/2 gallon of mixed fuel, make up a small fuel tank with fitting to the motor if applicable and run the motor at a medium speed let most of the fuel be consumed and shut the motor off. Pull the spark plugs, squirt more SeaFoam directly into the spark plug holes. Let the motor set for 20 minutes, then start it up. If you have carbon internally the motor will burn this loosened carbon which will SMOKE considerably.
I’ve done a similar de-carb using “Sea Foam” on several older outboards, with excellent results. Good luck!!
…Politicians aren’t the “Oldest Profession”, but the results are still the same!!!
Got the spark tester and the seafoam. I have one fuel tank with around a gallon in it, going to dose it with seafoam. If I dont burn all the gas with seafoam out I guess it will be ok to top the tank off and leave the last with the seafoam in it? Tonight I check compression and spark, aint it fun?
Compression was between 122-125 across all 3 cylinders. Hooked up the spark tester and had bright spark across 1/2 inch gap… maybe a fuel issue? Calling the mech tomorrow to see how busy he is I think
Compression was between 122-125 across all 3 cylinders. Hooked up the spark tester and had bright spark across 1/2 inch gap… maybe a fuel issue? Calling the mech tomorrow to see how busy he is I think
fmb3, there is a screw at the bottom and front of each carb. Pull the screws and see if gas comes out of them. My 65hp was running crazy like that and Chris V suggested the floats were sticking. Sure enough I pulled the screw on 2 and no fuel. Pulled the crbs and removed the bowls and yep , floats stuck.