1973 Johnson 115 weak tell tale

[bobsquatch]

I had an overheating problem last week so I checked all water passages, replaced the vernatherm and installed a tell tale in the top of cylinder #1. Runs cool on muffs but the pee stream is weak and sputters. I am not sure if this is normal but I doubt it. I am thinking of dropping the lower unit to look for trouble but I may just launch and see what happens. What do you think. I am thinking the impeller spun the key or the water tube guides popped off or something along those lines.

 

[emdsapmgr]

Your engine does not have a telltale. That came out with the 1978 models. There is a way to determine if the thermostat (vernatherm) is opening properly. Start the engine when it's cold. Hold the palm of your hand back by the two exhaust relief ports at the top of the midsection. Within maybe a minute or so, the engine will warm and the stat will open. When this happens you will see water droplets form on the palm of your hand. That's normal.

 

[bobsquatch]

Thanks but I installed a tell tale while I had the head off for inspecting the water jackets for obstructions.

 

[gm280]

bob, sound like it is time to install a new impellor now. Not hard to do, but if you haven't changed it in the last year or so, do that first. That will probably I your problem... JMHO!

 

[bobsquatch]

Brand new impeller already installed. I may swap out the housing and seals as I have them on hand just to see whats going on in there. I was just wondering what the tell tale should look like as they are not installed on this engine. It is my understanding that the water goes straight from the pump through the heads then to the thermostat so the tell tale I installed in the top of the #1 cylinder should be steady and firm 100% of the time. Any argument?

 

[Bosunsmate]

Brand new impeller already installed. I may swap out the housing and seals as I have them on hand just to see whats going on in there. I was just wondering what the tell tale should look like as they are not installed on this engine. It is my understanding that the water goes straight from the pump through the heads then to the thermostat so the tell tale I installed in the top of the #1 cylinder should be steady and firm 100% of the time. Any argument?

Not from me.
It might be a bit of blowby through a gasket into the cooling jacket

 

[bobsquatch]

Any particular gasket you are thinking about? Are you talking near the water pump or somewhere else?

 

[bobsquatch]

Ok so i dropped the lower and I am glad I decided not to launch. I found the guide tubes off the water pump coupling flange item # 84 in the following link http://www.*****************/parts/jo...xhaust+Housing
It would appear that my sustained high speed run made enough pressure to pop the tubes off. With them disconnected high volume water escaping at every relief is the only pressure left to get to the upper engine and is in sufficient under any load. I do not remember there ever being a grommet for the tubes and the parts breakdown does not show them. I am going to re seat them but does anyone have a trick to keep them in place?

 

[bobsquatch]

Well after further investigation I am wrong again. Tubes are just guides and hold no pressure. It was weighing on me to check the impeller key since I had the lower off. It was hard to remove until I was able to spin it on the shaft. The cheap impeller core is made of plastic and the key spun through it. I fortunately have a complete rebuild kit p/n 0439140 on hand with a good ole American made metal core. I will be installing the housing, wear plate and seals but the kit comes with an oring that I do not see where it goes. The only thing I can think of is on the top of the drive shaft below the splines. Is one supposed to go there?

 

[bobsquatch]

Bonus points to gm280 for calling it right even though it was a new impeller.

 

[bobsquatch]

Just got it all back together(oring on top of drive shaft). Strong pee stream at idle and running cool. We will see how it goes next weekend. Thank you all for your help.

 

[gm280]

Just got it all back together(oring on top of drive shaft). Strong pee stream at idle and running cool. We will see how it goes next weekend. Thank you all for your help.

Okay good to here you got it working now. And yes that "O" ring does go at the top of the drive shaft to help keep water out of the spline area. :thumb:

 

[oldboat1]

points to gm280, but didn't quite follow your description of the impeller failure. Know you are done with this, but any chance of a pic of the old impeller? The issue is typically that the key was left out or was dislodged during installation. Would kind of like to have a look at an impeller that might be prone to the kind of failure you describe.

 

[bobsquatch]

points to gm280, but didn't quite follow your description of the impeller failure. Know you are done with this, but any chance of a pic of the old impeller? The issue is typically that the key was left out or was dislodged during installation. Would kind of like to have a look at an impeller that might be prone to the kind of failure you describe.

The key was installed correctly and was still in place when I removed the impeller which made it difficult to get loose but because the key is so small 1/32 of an inch or so is all the difference between the key in the rest of the shaft. it ran great for many hours but I rarely ran it wide-open throttle and never sustained so long. The plastic core simply augured out where the key slipped through it from the excessive force of high rpm running I will post pictures when I figure out how.

 

[oldboat1]

yeah, curious. thanks. When writing a reply, click on the attachment icon on the right, and select a pic to attach. Works pretty well.

It sounds like you may have the wrong key, if I get what you are describing -- key should engage deeper/more securely than that.

 

[bobsquatch]

The key is the same one that came out of it and the same one that was in the kit they match identically so hopefully it is correct as far as uploading pictures goes it is always too big and when I resize them I ruin the picture for everything else.

 

[bobsquatch]

Not that it matters for technical pictures but for things I'd like to keep it bothers me. This site would get a lot more pictures loaded if the resizing was automatic through the forum.

 

[oldboat1]

No Title

will try one. (edit. not completely sure how I got there -- and ended up with a double post of the pic. guess just try camera icon too -- get the option to resize at one point. worth a second try. There are admin instructions (haven't gone to them just now -- kind of like asking for directions, or consulting the manual. guy thing, I guess....)

 

[bobsquatch]

No Title

I had to resize it twice but here is the hub of my new impeller that failed

 

[oldboat1]

Thanks -- extra effort is appreciated. That impeller issue is really interesting. Is that an aftermarket or OEM (think there is some opinion about some aftermarket failure, but not sure)? Positive it was the right impeller for your motor (dead on fit on shaft)? Using the factory key? My first thought is that it had to bind in the cup for the shaft and key to do that damage. Curious -- would like to avoid a similar issue (tough to troubleshoot, as you showed).