Johnson 1975 135hp waterpump kit replaced and still no telltall stream

[svanek16]

New boater here with some mechanical skills.
Just picked up a Procraft 17.5 fish & ski. Boat has a 1975 Johnson 135hp, I have not put in water yet.

I have replaced the following so far.
Both carbs redone with carb kits
1 coil replaced because it had a crack
Timer base, Stator, Power Pack, plugs, fuel lines, primer bulb and fuel pump replaced. Today I dropped the lower unit and performed a water pump kit replacement, I did not replace any themostats. Lower unit already had fresh oil from previous owner. Compression tests on all 4 cylinders are between 135 and 140.

Owner history, I purchased it from a guy who purchased it this spring from a church charity sale. says he had it out three times this year. I tend to disagree!!!!! He says he needed starter fluid to start it, but said it ran fine afterwards. Since the impeller was totally trashed I don't believe the boat was in the water this year.

OK, so my question. When idling I expected to see water squirting from the two openings in the rear of the motor, this did not happen. I know the drive shaft controls the water pump, so I put the engine in gear, still no water squirt. Is it possible the thermostat needs replacing? and do you think it's safe to take on the water in current conditions. it runs beautiful at home but I can't tell if the new water pump kit is working. Please help.

 

[jafiori]

Re: Johnson 1975 135hp waterpump kit replaced and still no telltall stream

Are you using ears or a barrel to run the motor in?

 

[l_striker]

Re: Johnson 1975 135hp waterpump kit replaced and still no telltall stream

Check the hose and the tip where the water spits out. The tips can easily get clogged with sand. Try blowing in the hose and if no air goes through it then use a small drill bit to free the blockage. If that's not the problem then did you remember to install the key when you put the new impeller in?

 

[Rick-va3rzs]

Re: Johnson 1975 135hp waterpump kit replaced and still no telltall stream

you should have water coming out or the motor when you have it in the water or on muffs

my question would be when you redid the pump how bad was it and did any parts get into the tube the feeds the motor ..

if you dont have muffs GET THEM .. and see if you can flush the motor .. take the T-stat off and see if water comes out ..

let us know

 

[svanek16]

Re: Johnson 1975 135hp waterpump kit replaced and still no telltall stream

Hey guys, I ran the motor both on ear muffs during idle and in a large container of water(intakes covered) in idle and in gear. Neither produced water coming out.

The old impeller was in real bad shape, the fins were none existent and the housing was full of burnt rubber from the old fins. There was a slight coating on the starboard intake tube which I wipped out. I didn't see any blockage.

Yes I removed the old key and installed the new one, I used a rubber mallet to install the new one. I lubed everything with motor grease too.

When motor warms up you can see air with slight smoke coming from the two holes that are supposed to produce water.

Two new questions.
1. What does "flush the motor" mean?
2. How do I replace the T-stat? seems I'd need to remove the powerpack and coils then remove all screws and open the belly under the power pack.

 

[Daviet]

Re: Johnson 1975 135hp waterpump kit replaced and still no telltall stream

If you are talking about the two exhaust ports on the exhaust housing, you will not see a stream of water coming out, more of a heavy mist. You will see more with the boat in the water as compaired to running on muffs because the exhaust fills with water when the boat is in the water.
Yuo should be able to hold your hand on the cylinder head for a 3 count, if running on muffs look for water coming out of the center of the prop, should feel warm.
You can install a tell-tale to show water pump operation.

 

[emdsapmgr]

Re: Johnson 1975 135hp waterpump kit replaced and still no telltall stream

DavieT is correct on this engine. The telltale setup did not come out till 1978. On your model you will get a water mist out of the exhaust relief holes after the thermostat (vernatherm) opens. This is usually about a minute after a cold engine start. If you hold your hand back by those exhaust ports, water droplets will form on your hand. That's normal.

 

[patrick4266]

Re: Johnson 1975 135hp waterpump kit replaced and still no telltall stream

Since you have done all that work you should install a "tell tale" on it. It will give you peace of mind and is very easy to do.

 

[Blue Fin 135]

Re: Johnson 1975 135hp waterpump kit replaced and still no telltall stream

I just went though this yesterday. (And thank you all who answerd me)

Same story, bought the boat and motor brought it home hooked up the muffs and nothing. Dropped the bottom end and found a whole new pump and impeller had been installed. On a lark I hooked up the muffs to the bottom end with the pump off...no water appeared..I walked over to the tap and cranked it up to full blast and suddenly watter started coming out of the pump cavity..I let it run for a few minutes, then I shut it down and slipped the bottom end back on, rebolted reconnected the linkage then I slipped the muffs on and fired it up. This time I turned the presser up a little on the hose and after 1 min water started shooting out the exhaust like it should...Neighbors enjoyed my driveway victory dance!!

Try the increased water flow...maybe it has been sitting and just needs a little washout??? Good luck

 

[Daviet]

Re: Johnson 1975 135hp waterpump kit replaced and still no telltall stream

When running on a hose ALWAYS turn the hose on full blast to get full water flow.

 

[svanek16]

Re: Johnson 1975 135hp waterpump kit replaced and still no telltall stream

Gentlemen,
Thanks for all your input.

1st, thanks DavieT and Emdsapmgr for the exact water pump operation of my 75 Johnson 135hp. I ran the motor for a minute or so with muffs on while holding my hand against the exhaust ports, 1st I felt cool moist air then after a minute or so it didn?t feel moist and the area between the cylinder heads got too hot to hold my hand against it. So I shut her down. Not sure the vernatherm is opening up!!!!!! You'll see below that the muffs don't work well by themselves.

I did some recon work and found the vernatherm, got a visual but was unable to remove and test it in hot water. I?m hoping it?ll work as designed. The visual looked ok. Christ could Johnson make the vernatherm anymore difficult to get too???? Wife wasn?t interested in going out on the water with me today, soo I??ll have to wait for a water test. It?s a pain to go out on my own!!! I?ll see if I can get a buddy with mechanical abilities next weekend. Living in Colorado the water is at least 1hr away!!!

Blue Fin 135, I dropped the lower end again and verified water output from the muffs. The muffs by themselves did not produce enough water, seems most of the water preferred to leak out the exoskeleton. So, while the lower end was down I pressed the muffs in tightly and got results of water pressing up through the waterpump housing into the inlets leading up thru the exhaust housing.
Bottom line, the muff are pretty much useless without manually squeezing them tightly.

I will look into installing a tell-tale. Let me know if I can find the instructions here somewhere in iboats or should I start a new tread about it.

Your expert knowledge is much appreciated!!!!
Here's a pic of the boat/motor.
Thanks