Johnson 35 1977 model dead in the water!

[sufferinghusband]

Hi All. Took my old boat out for a spin today. Travelled a couple of km's up the river, and turned to come back and the engine started to lose power and eventually stopped. Immediately after I had some smoke coming from under the engine cover. Managed to get a tow back to the ramp. Thinking it overheated, I tried to start it at home with the muffs on, but it just wont fire. Still turns over, and has backfired a couple of times but will not start. Took the cover off and it looks like the engine got pretty hot. Where there was old goo coming out of the head gasket, it is now crispy! The wires from the power pack were crispy as well, but tested ok. I have a feeling the head gasket is shot. My main question is can I take the head off the engine without removing the power head?? Any suggestions on what to look at first would be appreciated. I am mechanically handy, but never pulled one of these down. The engine appears to have been well maintained, but has had no use for a few years. I did have water coming out the tell tail and exhaust, but whether this stopped during my run today I dont know. Thanks in advance for any advice. Cheers

 

[racerone]

Re: Johnson 35 1977 model dead in the water!

Just take the cylinder head off and have a look.

 

[boobie]

Re: Johnson 35 1977 model dead in the water!

After you do that be sure to check the water pump.

 

[jbjennings]

Re: Johnson 35 1977 model dead in the water!

Be sure to replace the melted water diverters inside the water jackets under the head. I hear those 35's had some cooling problems.
JBJ

 

[sufferinghusband]

Re: Johnson 35 1977 model dead in the water!

Thanks for the advice thus far. I did some testing of the coils and power pack. They are all cooked! Am gathering the list of parts I need now. How are the plastic water jacket pieces held in under the head? I have played with enough car and bike engines but never an outboard, so am taking it slow. Have had to order a pressure tester today, and will not have it till next week. During the process I have found a few wires that are bare, that need fixing up. Surprising what you find when you are looking for problems! I am hoping that the electronics packed it in before any major damage was done. There were no noises when it stopped, it was just like being turned off. Fingers crossed. Once I get the pressure test done, I will update this post. Now to go reading up on the water jackets! Thanks all.

 

[Bosunsmate]

Re: Johnson 35 1977 model dead in the water!

Check your thermostat in a saucepan being heated, if it doesnt open it could of being your problem. Id probably replace that too

 

[Chinewalker]

Re: Johnson 35 1977 model dead in the water!

Before you spend any money on parts, be sure the motor isn't completely toasted. Getting hot enough to melt peripherals means it got hot enough to stick rings, scuff pistons and score the bore. Sometimes you get lucky, but usually hot means toast...

 

[racerone]

Re: Johnson 35 1977 model dead in the water!

Saw one get so hot that it melted the plastic on the center main bearing.--------Lots of these motors built and sold in the 80's that might be a better option.

 

[sufferinghusband]

Re: Johnson 35 1977 model dead in the water!

Havent got the pressure tester as yet, but have had a bit of luck. Someone local has the electrical parts I need so that will be a big help. He has a late 70's early 80's model Johnson 35 outboard that is pull start, and seems to think it has points. Would that be right? Were they different between electric start and pull start models? I can get the other engine for $250 so I am keen, but don't want to buy it if the parts are incompatible. Just waiting for that compression tester!

 

[racerone]

Re: Johnson 35 1977 model dead in the water!

Without exact model # it is hard to tell what is what.------The only year of that 35 HP type that had points was 1976.

 

[sufferinghusband]

Re: Johnson 35 1977 model dead in the water!

Well, the compression tester arrived. Prior to using it, I found the engine harness was shot totally. Just the engine harness itself was corroded. I don't know how it worked at all before my ill fated trip! Made up a new engine harness ok and got to testing. The compression was 12psi on each pot. I could have cried! I remembered reading about tightening the head bolts to see if it made a difference. Well, when I went to tighten the bolts, they moved a good 8th of a turn. All of them. Put the pressure tester back on and got 35psi. Pulled the water cover off the head, and managed to dig the thermostat out. I will up a pic of it later. I have never seen a thermostat in that condition, it was actually bent and broken, no water could get through it. Pulled the head, and was easily visible where it had been leaking into the water jacket. For a long time I suspect. The bores were ok, no discolouration. Only one score mark that I believe is old, as I could not even feel it with my fingernail. There was only a tiny bit of side to side movement in the pistons, and am fairly certain the rings are ok. Packed it all way, and am now waiting on parts to put it back together. I now have a day of cleaning the the head and cover. The water diverters appear to be solid, and in place. I don't want to pull them unless really necessary. They do not look melted or affected in any way. I think I will just leave well enough alone. What do you think? Safe? Cheers all.

 

[jbjennings]

Re: Johnson 35 1977 model dead in the water!

Sounds like you're good to me. Only way to be sure is to install the new gasket. I would flatten that head on a piece of glass and sand paper to be sure it's not warped.
Glad you had good news on the cylinders. I doubt i'd remove the water diverters if they look good.
JBJ

 

[HighTrim]

Re: Johnson 35 1977 model dead in the water!

Agree, dress the head. Change the t stat, and the impeller. Watch carefully on first outing.

 

[oldboat1]

Re: Johnson 35 1977 model dead in the water!

might run it in a tank first -- plastic garbage can? could do whatever tweaking is needed before boat testing (maybe torque head bolts again after she runs a little). all good.

 

[sufferinghusband]

Re: Johnson 35 1977 model dead in the water!


This is how the thermostat came out! I did not bend it or damage it in anyway. It had that much salt build up around the edges, it took a bit of careful scraping to get it out. I could not believe it. Thanks all for the advice thus far. Will let you know how it goes. Just waiting on parts. I am amazed at prices here in Australia compared to the US. You guys get it good! Cheers

 

[sufferinghusband]

Re: Johnson 35 1977 model dead in the water!

Still waiting on gaskets to arrive. In the meanwhile, I have been going through trying to find a write up on impeller changing. All I have been able to find so far, is to disconnect the gear rod at the power head end. This doesn't seem right to me. There is an access plate on the side of the leg, that I gather is to disconnect the gear shift rod mid way down. I can't seem to locate anything definate on the 1977 model 35hp engine. My manual is supposedly for the Johnson 35, but I think it is for the next model. Does anybody have a procedure for changing the impeller on this one?

 

[racerone]

Re: Johnson 35 1977 model dead in the water!

Correct , remove that plate and completely remove one of the 2 screwn in there to diconnect shift.--Just a simple job after that.

 

[sufferinghusband]

Re: Johnson 35 1977 model dead in the water!

Racerone, why did you have to say "simple job after that!"..... I have to laugh, it had to go wonky at some stage! It just wouldn't be my life if it came off that easy. Got the plate off no worries. Removed the lower screw, and the shaft was loose. Undone the four bolts holding the gearbox on. Then I noticed this nut........... It appears to be a stud from the gearbox, and it is bent. Since the attached photo, I have gingerly straighted it, and the nut still screws on ok, but it will not release! I have had it soaking in Inox, and even scraped old salt from around the thread. Can't get it to let go. Am I correct in thinking this bolt is holding the gearbox on? The rear of the gearbox is free, and the seal around the gearbox is broken, but at that front stud it just will not let go. It can probably move another 1mm, I am just scared I am going to make a right mess of it. If worse comes to worse, will hitting this stud to make it a little straigher do any damage that I can't undo? I cannot imagine how it got bent in the first place, but it seems that it must have been a while ago as salt has built up behind it. I know the studs are available if I wreck the thread, but I am more worried about damaging the gearbox where it screws in. It looks like it is well set into the cast, and am hoping it will move enough to let go. I am using a very big wooden mallet, and a steel punch to hit it. Sound reasonable?? Feel like an idiot, but just want to be careful.

 

[racerone]

Re: Johnson 35 1977 model dead in the water!

IT is easy on fresh water motors.------In this case it sounds like corrosion has jammed the stud.----A small propane torch is used to free it up.

 

[boobie]

Re: Johnson 35 1977 model dead in the water!

Get a Mapp gas torch as it has more heat and heat the area around the stud.