Newbie Here, Need some engine help... Please... 77' Johnson 35hp

[castires]

Good afternoon,

I'm having trouble with my motor. I bought the boat used from a friend. He told me that he had rebuilt the entire motor, pistons, rings, rods, etc...

I took the boat out 5-6 times with no trouble at all. Last weekend I went out with my son and the motor overheated. We were stranded for about 4 hours, but that's not the problem now.

So I took the gearcase off and the waterpump was burnt up, nothing left on the impeller but a round rubber disc. I replaced the waterpump, I also took off the front cover and back flushed the motor along with replaced the thermostat and buttoned it all back up.

The motor started on the first try, but ran rough, water was coming out of the hole, but the engine only ran for about a minute and shut off. I couldn't get it started again.

Yesterday I did a compression test and the results are below:

Top Cylinder - 105psi, added oil, went to 120psi
Bottom Cylinder - 120 psi, added oil, went to 130psi

Put the plugs back in and tried to start it. It fired right up and ran, still rough, but this time no water was coming out of the hole.

I'm really at a loss as to what to do. If anyone could offer me some advice I would be very appreciative.

This is my first boat/outboard, so I definitely don't know all the terms, but am willing to learn.

I do have a shop manual for the motor that he gave me, after reading it, it would appear the rings are bad, but could that be from the motor overheating or am I just missing something else...

Thanks,
Chris

 

[kfa4303]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

Hi castires. Welcome to iboats. I live up the road in Tallahassee. There are a couple of things that could be casing this. The simplest thing to do would be to check that the copper, water up take tube(s) is properly seated, both on the underside of the power head and on the top of the waterpump housing. We've all misaligned them at one time or another, and the grommets at either end can/do wear out over time. One trick to make sure that you've got good overall circulation through the power head is to properly seat the copper, water uptake tube to the underside of the power head, then use your garden house on about half power and hold it to the end of the tube (yeah you'll get a little wet). Hopefully, you'll see lots water coming out of the main exhaust port. If so, then your passages are probably ok. Now leave the tube in the power head and inspect the impeller. Put the lower unit in neutral by adjusting the shift rod, then rotate the vertical drive shaft CLOCKWISE only using your hands. You should feel a nice smooth motion and you should be able to see the impeller spin as you look down on to the top of the waterpump housing. If the driveshaft spins, but the impeller does not, then the impeller key may be missing/misaligned. Again, it's a pretty common problem and the key itself is tiny, but essential. Assuming, that the impeller is turning properly, make sure that the waterpump housing is seated properly. If it is not, the impeller can't/won;t pump water as efficiently. Give these tricks a try and check out this link that can walk you through an all around tune up and give you and exploded diagram of how everything should go together.

http://www.duckworksmagazine.com/04/s/columns/max/24/index.cfm (not exactly the same as your motor, but the basic steps are the same, especially regarding the waterpump and cooling system in general.)

http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1977&hp=35 ( just click on your model number for a complete parts manual with exploded diagrams of your entire motor. It should help you see how it goes back together and/or help you order parts when/if the time comes. You can get virtually any parts you may need right here at iboats too. )

Holler if you get stuck.

 

[castires]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

Thanks kfa4303, I'll take the lower unit back off tonight and give those suggestions a try.

As far as the rings are concerned and the compression, am I looking at a rebuild on this motor? Can that be caused from the motor overheating?

 

[castires]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

The model number on the motor is 35E77C, if that helps anyone.

 

[jasper60103]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

Thanks kfa4303, I'll take the lower unit back off tonight and give those suggestions a try.

As far as the rings are concerned and the compression, am I looking at a rebuild on this motor? Can that be caused from the motor overheating?

Just curious, did the motor show signs of an overheat, like discoloration?

 

[castires]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

Jasper, I don't see any signs of discoloration. I can explain what was happening when it occured.

I was probably at 50% WOT, cruising along. The boat lost power suddenly and came off the plane. I thought it was knocked out of gear or something...

I noticed there wasn't any water coming from the hole, and noticed smoke coming from under the cowl. I shut the motor down and removed the cover, it was obviously warm, and smoking from the heat. I waited about 30 minutes for it to cool down, then restarted it, it started just fine, however I still had no water from the hole, so I shut it down and called a friend to come tow me in.

 

[castires]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

Yes, my friend rebuilt the motor. He was the previous owner of the boat. He said he put in about $800 worth of parts into it. New Pistons, Rods, Bearings, etc... I have no reason to doubt that, but I also didn't perform the rebuild and therefore don't know how it was performed or his level of mechanical abilities.

I really don't want to shell out money for another good running motor. I would rather find knowledgeable people that could help assist me in diagnosing and fixing the current motor.

I love working on cars, but just never have ventured into boat motors, or had the need to until now. I understand the basic concepts of the 2-cycle engine, but still am hesitant to jump into rebuilding one.

Is that what you think needs to be done at this point?

 

[jasper60103]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

Yes, my friend rebuilt the motor. He was the previous owner of the boat. He said he put in about $800 worth of parts into it. New Pistons, Rods, Bearings, etc... I have no reason to doubt that, but I also didn't perform the rebuild and therefore don't know how it was performed or his level of mechanical abilities.

I really don't want to shell out money for another good running motor. I would rather find knowledgeable people that could help assist me in diagnosing and fixing the current motor.

I love working on cars, but just never have ventured into boat motors, or had the need to until now. I understand the basic concepts of the 2-cycle engine, but still am hesitant to jump into rebuilding one.

Is that what you think needs to be done at this point?

Can't say if a rebuild is in order, hopefully not. I'm sure the pros will chime in.

 

[kfa4303]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

The fact that is restarted after the over heat is a good sign. Hopefully, it didn't do any permanent damage. I know it may seem obvious, but make sure you're running the correct fuelil mix for your motor. I believe you should be using a 50:1 mix, which is approximately 2.5-3.0 fl.oz. of oil per gallon of fuel. Some folks even choose to run a little extra oil just to be safe. Thankfully, the cooling systems on these old motors are pretty simple and generally fail due to a simple mechanical error, like the ones described above. The trick is to investigate and eliminate problems in as systematic a manner as possible. Once one variable has been eliminated, move on to the next, rather than jumping around trying to fix multiple problems at once. For engine issues I literally start a the top (flywheel) and work my way down. For cooling system issues, I generally start from the bottom (gear case) and work my way up.

 

[castires]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

I'll pull the lower unit tonight and check the copper tube and make sure the waterpump impeller is spinning. I'll post an update once I check her out.

 

[lindy46]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

"So I took the gearcase off and the waterpump was burnt up, nothing left on the impeller but a round rubber disc. I replaced the waterpump, I also took off the front cover and back flushed the motor along with replaced the thermostat and buttoned it all back up."

The rubber from that old impeller had to go someplace - I'd suspect it's clogging the water passages, unless you were able to retrieve the pieces.

 

[castires]

The vast majority was found clumped up in the waterpump housing. After removing the thermostat I found 2 pieces behind it.

Is that all of the pieces, I have no clue.

I'm new to outboards, where else could pieces be?

 

[Home Cookin']

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

I'm wondering about your comment that you added oil and it affected the compression--to what?

I have also known old OMC's to overheat (oil or water) and bog down, cool off, restart, run, bog down again. The heat twisted the metal and it shows when it heats back up again.

Did your friend who rebuilt it, run it after rebuilding it? Comply with break in? Why did he have to rebuild?

Unless you'd rather wrench than ride, you'd be better off finding another motor than spending a few hours and part $$ on a 35 year old motor, worth $500 if running. Especially if it's a saltie.

 

[castires]

I added oil to the cylinder as per the manual and then rechecked the compression.

Yes the motor ran fine after his rebuild. I personally took it out 5-6 times with no trouble.

I'm not sure the reason for his rebuild but he told me that he had the block bored and surfaced as well as the head.

 

[HighTrim]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

A '77 is old? Geesh I dont think I have one that new! My newest motor is a '76 55hp on the fishing boat. I have motors from the 20s that idle like a charm and dont miss a beat.

All that may need to be done is get the waterpump working as it should. Dont throw that "old" girl to the scrappers just yet.

 

[F_R]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

castires, I hate to tell you this, but...
I see you are in Florida. That '77 model is a poor choice of a motor for Florida waters. '76 was even worse. We have too many weeds in our waters. The water intake on that motor is too easy to block with weeds. And when it does, it burns up the pistons. That might be why your friend had to rebuild it.

I live in Florida and worked for a Florida Evinrude dealer when that motor was new, and we actually stopped selling them for that reason.

Anyhow, your compression test says something is damaged by the overheat. If you are lucky enough, it may just be the head gasket and exhaust cover gaskets. But don't count your blessings till you examine it. The pistons may be (likely) cooked too.

 

[castires]

Well I went home tonight and started tinkering. What I found was that a connection was loose on the top of the motor causing me to loose spark.

I seated the connector fully and she fired right up. I took a picture of the offender, as well as a video of the motor running.

I'll upload them in a few minutes. She's smoking quite a bit and jarring around. It used to smoke a little before but not this much.

Could it be from the oil I added to the cylinders burning off?

 

[castires]

Yes it definitely clogs a lot. But it's what came on the boat and if I can get her to last a while that'd be great.

 

[castires]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

Here is a video of the motor running:

[video]http://s1192.photobucket.com/albums/aa321/castires/?action=view&current=IMG_1080.mp4[/video]

Here is a pic of the culprit plug:

Here is a pic of the water and the gunk that it has in it after running for about 5 minutes:

 

[Joe Reeves]

Re: Newbie Here, Need some engine help... Please... 77' Johnson 35hp

Smoke coming out from under the cover?....... The engine was overheated to a point of seizing, and yes, that powerhead is discolored.

Overheating to that degree..... most every bolt screw on that powerhead is loose due to the extreme heat, especially the head bolts. In all probability the failing head gasket is allowing the combustible power to enter the water passageway and/or allowing water traces to enter the cylinders.

Remove the cylinder head, clean the sealing surfaces of the head and crankcase, install a new head gasket and tighten/torque the head bolts to 18 to 20 foot pounds in the following sequence.

9....10
5.....6
1.....2
4.....3
8.....7