1977 35hp Johnson noises.

[old islander]

I guys,
I picked up a 77 35hp Johnson not running last year. Turns out it was the needle stuck in the seat so after a cleaning it runs great now. Heres the other issue. It has a knocking noise coming from inside the leg. It sounds like the shaft is hitting something when it turns. The PO said he put a water pump in it last year ( don't know if it was full kit or impeller only). The motor is pumping plenty of water with a very strong stream from the pee hole and is spitting plenty of water from the rear of the leg. Whats weird is it is also pushing a lot of water out the front of the leg (see photos). Is water supposed to be coming out here? or could this have something to do with the knocking,rubbing sound coming from the leg?

 

[bonz_d]

I think you should pull that lower unit down and see if you can find where the noise is coming from. Could cause serious damage.

 

[gm280]

If that is plumbed correctly from the water pump assembly, I can't see how water would come out any place put the usual pee tube and the exhaust outlet. Any other place means there is something not quite right going on. And I would be hesitant to run it anymore until you figure out what is wrong with the knocking noise... I can easily see the two issues combined! JMHO!

 

[F_R]

No Title

I am posting this picture to illustrate how and why concerning the water coming out the big drain holes in front: It is NOT the same exhaust housing as what we are discussing here, but it is the same situation.

The drive shaft runs in an isolation tube. That tube is continuous with the water pump housing via a seal or oring or whatever. Water escapes from the pump housing, through the hole the drive shaft passes through. That is intentional, to provide a water seal around the shaft and prevent air from entering the pump. So, where does all that escaping water go? Well if not for the drain holes, it would fill the isolation tube and possibly enter the powerhead through the lower crankshaft bearing. Thus, the large drain holes to prevent that possibility.

 

[bonz_d]

I'll add that by the manual for the 50hp 2cylinder models that water is also used to cool the outer exhaust tube from the hot gas exiting the inner exhaust tube. Those 2 cylinder 20-35hp use the same 2 exhaust tube set-up with an inner tube and outer tube.

 

[old islander]

Well a little more investigation and I think the noise is actually coming from the flywheel area. The motor idles nicely and revs up well with no hesitation. The noise does not change of get louder when running at speed. I think I can rule out a rod knock. Going to have a look under the flywheel for rubbing components, bushings,..etc.. One more question. When I run it at speed and then return it to idle it dies. Then restarts with a bump of the key. what would cause it to die when going from WOT back to idle?

 

[F_R]

Well some of that is inherent in a two stroke, however today's motors pretty much have it eliminated. At idle speeds, the fuel sort of settles out of the air as it passes through the crankcase and in older motors puddled up in the bottom. The carburetor is adjusted at idle to compensate for that. But when you open the throttle to go fast, the puddle blows out. When you suddenly slow down to idle, there is no puddle there and it runs a bit lean and may stall. Today's motors have the situation pretty much under control, but a sudden return to idle can still see a lean condition. Check your idle mixture adjustment on the carburetor and possible tweak it a little richer. Also, if idle RPM is set too low, it may stall under that situation.

 

[old islander]

That brings up another question. Where do you adjust the idle speed on these motors? Thank you for your patience F R, This ones kind of new to me.

 

[Drummerhowie]

Yeah that water coming out of the front is normal....my '84-30 hp Evi does it also, and I just went through the lower unit/water pump.