Temperary engine binding

[brynifer]

I know I read something here a while back related to this but can't find it now. Did'nt have the problem until today.
1973 135 evinrude, after running alittle under WOT for about 1/2 hour, the engine gradually slowed down, as it did it started knocking very loudly , then died.
On restart try the starter just jammed on the flywheel.
I pulled the cowling and was able to turn the flywheel by hand so I went back and tryed the starter again. It started right up but was still making the knocking, being in the middle of nowhere I put it in gear and started creeping home. I then noticed the knocking was fading away. I gave it alittle more juice and it was fine. When I got near my creek, I opened it up and it was totally normal.
I know I read recently about a coupling under the water pump that, when worn can expand and jam the drive shaft. Could this be my problem?
The only other weird thing that the engine always did was that, again, after running near WOT when brought back down to idle the engine does not fully return to idle speed in neutral, it races slightly and sounds almost like it's having pre-ignition. After a minute it slows to a normal idle.
It is not over heating and from a visual inspection through the sparkplug holes, I see no carbon. Top of piston is clean, I did use a few cans of carbon remover anyway but it made no improvement.
I'm alittle afraid of this thing now because my dad's boat (for rescue) is out of the water. Not many boats on the bay in November.
Any input is welcome,, Thanks

 

[Silvertip]

Re: Temperary engine binding

Was not overheating from visual inspection? Except for discolored paint you can't "see" overheating (just the effects of failure caused by it). Sounds very much like overheating to me and subsequent seizure until the engine cools. Better investigate the water pump impeller, alarm system, fuel mix (50:1), air leak around carbs or manifold and the condition of cooling system.

 

[bktheking]

Re: Temperary engine binding

I second overheating , do you have laser thermo you could point at it to test the temp, should be around 140F on both heads at all times.

 

[brynifer]

Re: Temperary engine binding

Over heating was my first thought, however when I removed the cowling, I put my hand on the heads and was able to keep it there. I did this immediatly after it died. If anything, it felt somewhat cooler then I would have expected normal running temp to be.
Also when it started again, only a few minutes later, I saw it was pumping plenty of water.
I do have a temp gun I plan on taking it with me on the next outing.

 

[brynifer]

Re: Temperary engine binding

Just remembered, Last month I checked the overheat buzzer by jumping the wire of the senser to ground and it worked, I did not ,however actually check the sensor. As I remeber it did'nt look like it would easily remove from the engine.

 

[kenmyfam]

Re: Temperary engine binding

Did you check both heads ???

 

[F_R]

Re: Temperary engine binding

You mentioned the shock absorber under the water pump. 'Tain't that--it doesn't have one.

 

[brynifer]

Re: Temperary engine binding

Both heads? to be honest I don't remember. I don't think I did though, I know I approached the engine from the starbord side where the overheat sensor is and that head was cool, would explain why I did'nt hear the buzzer.
Is it possible for just one side to overheat? I never considered that. I'll find out tomorrow. If anything, I always heard that if an engine is going to over heat, it would be the starbord side first.
I did'nt think it had any kind of coupler but was'nt sure. It does sound very much like overheating .
I thank you all for responding

 

[kenmyfam]

Re: Temperary engine binding

Both heads? to be honest I don't remember. I don't think I did though, I know I approached the engine from the starbord side where the overheat sensor is and that head was cool, would explain why I did'nt hear the buzzer.
Is it possible for just one side to overheat? I never considered that. I'll find out tomorrow. If anything, I always heard that if an engine is going to over heat, it would be the starbord side first.
I did'nt think it had any kind of coupler but was'nt sure. It does sound very much like overheating .
I thank you all for responding

It will overheat wherever a blockage or restriction is. It will not be fussy as to which side it is.

 

[brynifer]

Re: Temperary engine binding

I guess I just assumed that the water had one path through the engine and any blockage would stop all water flow, but then you know what they say about ***-u & me-ing. Or, just me in this case.
I'll stop and check it every few minutes on the way back to the boat ramp in a week or so. It will be a fun winter project.
thanks again for all the input. I'll be sure to return some to the forum

 

[R.Johnson]

Re: Temperary engine binding

I once had a small Checkmate performance boat. I looked a long time before I found a l973, 135 HP. That engine had alot of performance at a lite weight for it's time. It was not uncommon for one to go BANG, thus making a good one hard to find. Knowing that engine, I would take the head's off first thing. How long have you had this engine, and did you ever have it rebuilt?

 

[reeldutch]

Re: Temperary engine binding

were are you located on long island may be i can help you out?

 

[brynifer]

Re: Temperary engine binding

I have only had the boat/engine for one season. It had been sitting in a neibors yard for about 10 years. One day I stopped by to ask about it and ended up taking for nothing. he told me the last time he had it out he blew the engine. I took it anyway because the trailer had potential and the hull is a 68 thunderbird, very similar to the boat they used on Flipper. I like those cathedral hull boats. It has no significant rot, good hard floor.
I did a compression test on the engine after removing the lower unit because it was jammed. I got a used one from a salvage guy and installed it, rebuilt the carbs, replaced battery cables and some other hardware. I soon had it running. Aside from a slow cranking starter, it ran pretty well.
As for the offer for help, I'm not ready to take anyone else's time with this. I'll keep the offer in mind though, thankyou.
I did'nt plan on continuing this thread so long but all you guys are being great, so here's today's update
I gave it a running today with my temp gun onboard. After coming down from about 3/4 throttle I ran in neutral long enough to hear it doing that fast idle-pre ignition thing and then immediatly shut if off and went right back with the temp gun, I had already had the cowling off.
Hearing the fast idle, i figured it must be getting too hot again, however, my gun showed 135 degrees as the hottest reading of several areas on both heads/cylinders. I went all around the heads with the gun, holding as close as possible. I'm wondering now if there is so much corrosion in the engine that it's not transfering the heat from the cylinder walls to the water. I"m measuring the outside of the block, not the actual cyllinders.
How's that for a theory?

 

[reeldutch]

Re: Temperary engine binding

i dont think its overheating.

i do think its running lean.
when you run around at 4000 it wil run all day without this problem?
if it does let me know i had a similar problem this year with a 60hp johnson did a lot of work on it but still did the same thing.

turned out to be a kinked fuel hose not giving it enough fuel at wide open bud just could fill up the carbs around 4000.

so what im saying is its a fuel problem not a cooling problem.
its hard to explain because i couldnt figure it out either but its the piston skirt that is expanding deu to preignition.
when it happens hit the primer or squirt extra fuel into the engine see what happens.

 

[brynifer]

Re: Temperary engine binding

there's a thought!
I guess you would never hear pinging at hi speeds. I know the fuel lines are fine and I think the pump is too because I have sqeezed the bulb as it was loosing power and also at the fast idle times and it built pressure right away and made no difference in the way it was running. Having rebuilt the carbs, it's entirely possible that I have the float levels messed up.
when I was tuning the engine, I went with the suggested chanpion flush gap sparkplugs, I found them to easily foul, I think we got half way through the season with them. Even after running accross the bay, they remained wet and sooted.
I went to a conventional gap ngk plug with a little higher heat range and they are much better but still do not completely dry out. Could it be running lean and still have wet plugs? Maybe I also have an ignition problem.

 

[reeldutch]

Re: Temperary engine binding

i would suggest to go back to the recommended spark plugs.

defenatly check the float levels.
make shure all fuel lines are nise and tight no air leaks.

pressurizing and checking if it drips doesnt mean its air tight when you put vacuum on it.
can work like a check valve.

you didnt answer my question if it keeps running happy at 4000 all day long?

 

[R.Johnson]

Re: Temperary engine binding

The man you got it from said it was blown up. What was done about that?

 

[brynifer]

Re: Temperary engine binding

We used the boat all summer to go accross the bay, about 20 min each way at around 4000rpm, never had a problem while under way. We never actually ran the boat "all day". The tach is old though, may not be accurate, I probably should but a known good one on just to double check WOT speed. This one says around 5000 but the needle moves around alot.
"Blew the motor" was more the guy's choice of words. Like I said, What I found was the lower unit would not rotate 360 degrees. I would guess that the last time he used it , the motor just stopped and that was it.

 

[R.Johnson]

Re: Temperary engine binding

What I'm getting at, when a engine make's a strange noise, there is something wrong. It does'nt heal up with a little rest. As I also said, I personally liked the 1973, 135 because you could wring out a lot of performance for it's size. As time went on with that engine, fuel quality could be a real problem. I would not spend one cent on a 135 with out a compression test, and I would'nt really trust that. I would take those head's off. I still have the power head to one of those engine's in the shop. Like most I found, it need's to be rebored for a new piston.

 

[jpwade_bsu]

Re: Temperary engine binding

What I'm getting at, when a engine make's a strange noise, there is something wrong. .......

maybe check your lower unit and change its oil, a faulty gear case could put excessive load on the powerhead, maybe just the lower unit oil, noise from the lower end will travel up and pretend to be a block noises.
joe