Not getting water to heads on muffs on 1985 johnson 115

[crb478]

I have a new to me rebuilt 1985 Johnson 115 that is not getting water to the heads, but it is pumping a good stream of water out of the tell tale. I bought this motor from a shop that went under and it had taken a fall and cracked the lower cowling. I recently located a compatible lower cowl and switched the two. I cranked it up and after a few minor issues like hooking up the enrichener lines and correcting the coil wires got it running well, but it quickly overheated on the muffs setting off the alarm.

I have verified that the diverter tubes are in place and not blocking the flow, the head gaskets are on correctly. I pulled the water jacket covers off the heads and they are clear as are the heads and water passages around the cylinders. The tell tail is located at the botttom of the bubble back exhaust and water will start flowing to it with in a few revolutions of the motor even when it is not running. The thermastats are new as it the impeller.

All of this is being done on muffs. I read an old post where someone said that they could not get their motor to cool properly on muffs but it had to be submerged and then it ran fine. Has anyone else run into this issue. The water comming out of the tell tale indicates to me that it is hooked up correctly. I really don't want to go it down to the boat ramp and block it up trying to see if it will run without overheating if I am missing something.

I appreciate any ideas that anyone may have. I have ordered new water passage gaskets so I will be down a few days anyway. Otherwise I guess I will have to try to put the boat in and see if it will run correctly. I have had other 115's and they all ran fine on muffs.

 

[Joe Reeves]

Re: Not getting water to heads on muffs on 1985 johnson 115

On a flushette, the hose must be on full force on that engine. Is it?

 

[crb478]

Re: Not getting water to heads on muffs on 1985 johnson 115

Thanks for the reply Joe!

It is on full force and one I have used on other motors. It does have some water that leaks around the cups but that is not uncommon either. Can you see any reason it should not be getting to the heads other than not getting enough water or water pressure through the hose? I believe that I will try to back the boat down a ramp and try starting the motor with it still on the trailer and see it the heads get hot once I get the water passage gaskets back. Hopefully on a slow day where the boat will not be in anyones way very long.

 

[V153]

Re: Not getting water to heads on muffs on 1985 johnson 115

Sounds odd. Not trying to be a smart a** but doesn't a tattle tale tell you that water is indeed circulating through the jacket? I dunno that you'll see an improvement with it in the water, my crossflows run fine on muffs. What alarm are you getting. If memory serves me the high temp alarm is a constant "BEEEEEEP". Can you run it and shoot the heads with one of those infrared thermometers? How confident are you that the thermostats and/or impeller are new? Is the water from the pee hole scalding hot? What is your water pressure?

Sorry to hand you more questions than answers. Having owned several of these motors I'm interested in finding the problem as much as you are. Keep us posted.

 

[crb478]

Re: Not getting water to heads on muffs on 1985 johnson 115

positive that both thermastats and impeller are new. The heads are getting hot and it is a constant beeeeeep. It has a factory bubble back exhaust and the pee streem is located at the bottom of the exhaust housing and the water is not scalding. I am starting to think that with the tell tale that low it may not be allowing the heads to fill up without the pump being submerged or maybe the muffs are shot since they do leak around teh contact points. I have run many other crossflows on muffs with no problem, but most have been flat backs. Maybe the bubble back needs more water or the tell tale needs to be close to the top of the housing.

 

[Joe Reeves]

Re: Not getting water to heads on muffs on 1985 johnson 115

Assuming that the water pump is in perfect condition and the water passage to the powerhead is not clogged solid, the only condition that I can think of that would prevent water from flowing to the powerhead is a failing head gasket that would allow combustion to enter the water passages which would result in a water/combustion stalemate..... meaning that the water could rise only so far, meet the powerful combustion, travel no further, and just sit there and boil.

To test for blockage, remove the lower unit, disconnect the short hoses that lead from the cylinder heads to the thermostat housing, connect the garden hose to the copper water tube and turn it on. If no blockage, water should flow freely out of both cylinder heads.

You may be able to get the water to flow to the powerhead without removing the lower unit via the flushette route but it's best to have a direct route (hose to tube).

 

[Haffiman]

Re: Not getting water to heads on muffs on 1985 johnson 115

The answer might be in the statement: The thermostats are new.
Do the thermostats have bleed-holes to get rid of the air?
If not, you will have an air-cushion preventing water to reach the thermostats and let them open.
When submerged, in 'clean' water, a slight rpm increase will manage to pressure enough water, but on muffs, the water entering is normally mixed with air and makes it all worse. Try to either launch the boat or submerge in a bucket.

 

[emdsapmgr]

Re: Not getting water to heads on muffs on 1985 johnson 115

The telltale is plumbed into the block where the water from the lower unit goes first. It is a good indication that the impeller is working ok. Not that the water is circulating through the block. The block water exits at the thermostat housing. Likely you have good water to the block, but it may not be going out and down the lower unit. 1. You can test that theory by running the engine and pull one of the large water hoses off that go into the stat housing-from one head. Should be a lot of water... Then try the other hose. Same thing. Reconnect the hoses. Test 2. rev the engine up to 1500 rpm's temporarily. This will force open the pressure relief valves inside the thermostat housing. You should see increased water flow from the exhaust relief ports. This indicates that the pressure relief valves are operating normally, not that the stats are open. Under this scenario, the engine would likely not overheat when on plane. Might overheat when idling. 3. If both hoses show significant water flow, and the pressure relief valves seem to open, then your problem is somewhere inside the thermostat housing-probably the stats. You would likely get an overheat at idle. One last thing to check, the flat plate inside the thermostat housing (the valve body) has two pinholes in it. One for each stat. These must be open, as they permit hot water to bleed to the back of the stats and cause them to open. These frequently fill up with debris over time and block the water flow. Usually this should be checked when new stats are installed. If the holes are blocked, you will get an overheat at idle even though the stats are new. I've attached a picture of a 1989 valve body and the pinhole in the bottom middle of the picture. (this is a later body) Likely your body has two of these pinholes, one for each head. You can see how easy they might plug up with any silt, weeds which get sucked up during normal running.

 

[Haffiman]

Re: Not getting water to heads on muffs on 1985 johnson 115

As a comment to the above:
Even with the bleed holes open, running on muffs with no back pressure, water going through may just drain out and not reach the thermostat elements. To be sure the thermostat elements gets water, the thermostats themselves must 'leak' slightly.

 

[V153]

Re: Not getting water to heads on muffs on 1985 johnson 115

Maybe the bubble back needs more water or the tell tale needs to be close to the top of the housing

Nonsense. The bubble butt has a slightly larger cavity to fill, initially. Flat back, bubble back oughta pump about the same after running for a minute or two. Provided the water pump's in good shape.

 

[crb478]

Re: Not getting water to heads on muffs on 1985 johnson 115

Thanks for the suggestions, honestly I do not remember seeing any bleed holes in the thermastats, but I am not sure one way or the other. That does make since though. When my gaskets get here I will try to lanch it and see if that helps. Thanks again everyone I am sure I will have it going soon.

 

[crb478]

Re: Not getting water to heads on muffs on 1985 johnson 115

Just to follow up on this thread incase it helps someone in the future and to thank everyone who posted helpful suggestions.

I took the boat to the boat ramp yesterday morning when it wasn't crowded and backed it down the ramp leaving it on the trailer. After a few frustrating minutes trying to get it to start which I believe is probably related to the double oil for breaking it in I got it running and and the motor did not overheat so Water is obviously now getting to the heads and cooling. I let it run for about 15 minutes before cutting it off at rpm's from idle to about 1800. Once warmed up it also started back up on the first revolution. This motor seems to do fine once the pump is submerged and may do better on mufffs once the thermastats wear in some. Hopefully I will get it out in the next few days with enough gas in it to actually start breaking it in.

Thanks again to Joe Reeeves, you knowledge amazes me as always, endsapmgr and Haffiman, your insight was dead on in this situation. Thanks Again!