Pump issue

Joined
Mar 8, 2020
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20
Git an 84' 50 hp I just installed in my boat. Hasn't running almost 6 years but I got it to fire. All seems well except that it wont pee in idle in neutral. The moment I throttle up it will pee and if I put it into gear, even at idle it will pee. Is this normal? I was told it was normal because if a thermostat. New to this size of motor.
 

racerone

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Dec 28, 2013
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As soon as the motor starts it should pee !!------Install a new impeller now.----Thermostat has nothing to do with the pee stream at all.
 
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Mar 8, 2020
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Ok, have to find someone local to do it for me. Seals may need replaced as well, got oil coming out the prop
 

racerone

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Dec 28, 2013
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A 84 Mercury 50 HP may not even have a thermostat.------Impeller is easy to replace if you want to learn to save $100 / hr charges.
 
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Mar 8, 2020
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So I tried to remove the lower unit, removed all 5 bolts, drops about 1/4" then it stops. Friend suggested it may be the drive shaft sticking but he was unsure how to proceed.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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read the factory service manual, it will tell you the procedure and why it only drops 1/4"
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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you need the drive in forward to allow the shift linkage to come apart. that is covered
 
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Mar 8, 2020
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So, found a couple videos and articles on line, all said the same thing, the grease on the drive shaft splines gets old and hardens, almost like a glue. Everyone has had to turn the motor upside down and spends days spraying degreaser down the shaft and let it soybean away at the grease.
 

racerone

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Dec 28, 2013
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Don't think so.--------If it came down 1/4" the driveshaft is not stuck / seized.--------Perhaps some plastic wedges and a bump from a small mallet will get it apart.-----Forward / neutral / reverse does not matter either.
 
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Mar 8, 2020
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Don't think so.--------If it came down 1/4" the driveshaft is not stuck / seized.--------Perhaps some plastic wedges and a bump from a small mallet will get it apart.-----Forward / neutral / reverse does not matter either.

i am gonna make some wood wedges, that way i know the wood will go before i break the housing.
 
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Mar 8, 2020
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Still ain't got the lower unit off. But I was advised my mark at Mark's mercury in Salem that because this motor was used in saltwater, the shaft is more then likely rusted in. He suggested to drill a 1 inch hole in the middle housing just down from the head unit then spray the shaft several times a day with pb blaster. May take a week to get it lose.
 

racerone

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Dec 28, 2013
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38,438
Put the lower unit back up to within 1/8" of the exhaust housing.----Couple of nuts will hold it in place.-----Put the muffs on and start it up.----Vibration / shaking will likely loosen the rust.------Run for 5 minutes.
 
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