old Johnson 70 runs great but water in engine compartment

[dsujen]

I have a model# 70el78c motor that has great compression and runs great. I took it out on the water 3 times with no problems.
.
At the base of the powerhead while running, about 2 inches of water comes in while on muffs in the driveway inside of the engine compartment. But it leaks to the outside preventing the water level from getting too high. I thought maybe the water pipe from the water pump was installed wrong. Before buying the new water pump assembly I talked to a good old timer outboard mechanic. He's not a "parts changer" mechanic. He gave me some free advice over the phone. He said don't waste your money on the water pump assembly and run it till it blows up because to fix that kind of a leak requires removing the power head and four bolts at the base that are impossible to remove to replace a gasket. My question is: does this sound right? And how long do you think I can run this motor like this because it really does run great.

 

[orbanp]

Re: old Johnson 70 runs great but water in engine compartment

Any chance that it is a warped exhaust cover?
You could watch the motor without the engine cover and you might see where the water is coming from.
If it is a warped exhaust cover then you might want to fix it. Water could get into the cylinders as well, through a warped and leaking internal plate, and that would ruin your engine quickly.
These engines are known to warp those components. Do a search, it was discussed in great detail here.

Peter

 

[hardwater fisherman]

Re: old Johnson 70 runs great but water in engine compartment

my 1976 40hp had a bad exhaust cover gasket. and water would leak out the bottom of the exhaust cover and settle in the bottom of the cowl. it got to the point where when ran at wot the ignition would get wet. this summer i was on vacation and i put some rags in there to soak up the water. i have since changed the exhaust cover gasket and it is ok now. also one bolt worked itself right out an 2 more could be taken out by hand.

 

[boobie]

Re: old Johnson 70 runs great but water in engine compartment

Find out where that leak is and get it fixed before something really bad happens to your power head.

 

[dsujen]

Re: old Johnson 70 runs great but water in engine compartment

how hard is it to get to the problem area? Do I need to remove the power head or just remove the lower unit? Is it worth working on? I bought the boat cheap and am willing to buy another cheap motor that is a little newer with power trim.

 

[boobie]

Re: old Johnson 70 runs great but water in engine compartment

As I said above, find out where the leak is definitely coming from and go from there.

 

[kodibass]

Re: old Johnson 70 runs great but water in engine compartment

It is not that hard at all to pull the power head, unless the engine is a long time salt water engine you may run into some corroded bolts. If the motor runs well as you say, fix the problem and while the PH is off replace the exhaust cover & baffle-gasket. freshen up the paint on things etc. etc. you will feel much pride in doing so & will have greater confidence in your cared for old/new Johnson 70.

 

[dsujen]

Re: old Johnson 70 runs great but water in engine compartment

I don't have the shop manual. Anything special I need to know like shifter position or techniques?