1979 Evinrude 140 Power loss.......need suggestions please.

[Theoutdoorsman]

Motor coughs at an idle and is sluggish when throttled up. It takes 10 times longer to plane than normal now and won't turn the usual rpm's at WOT. This is a problem that has progressively gotten worse. The carbs have been freshly rebuilt by a mechanic, fresh fuel in the tank, new water seperater installed, and all fuel line replaced. No change in performance, although the cough at an idle is almost non-existant now. When I bought this motor 1 1/2 yrs ago, it had been rebuilt by a mechanic and ran like an absolute dream the first year. Seldom ever at more than 4500 rpm's. A little history on the motor........On three seperate occasions, all at different times of the year, the motor died at WOT as if it were running out of fuel and ultimately shut down. Each time, it would not turn over until it cooled down for about 5 minutes. It wouldn't even try to turn over. It was almost as if the battery was dead. Once it turned and started, it ran fine. Then, it didn't do this again for two or three months. Same thing the other two times. Hmmmm........end of history. At any rate, I now have the above mentioned problem. Any suggestions on trouble shooting this? I REEEEAAAALLLYYY want my 140 back as I'm sure you guys understand!!!! This has really puzzled me. At first I thought maybe the pick-up in the fuel cell might be clogged, but now I'm not sure. A service manual, owners manual, and parts manual are all in-route to my house as I type. I'm kind of ignorant when it comes to motor repairs, so any and all help would certainly be appreciated. Thanks in advance.............ALAN

[HOUSTON1]

I had a similiar prob with my 1977 140 (died will running down the Intercoastal waterway WOT), but mine would turn over afterwards and immeadiately afterwards would barely run with throttle advanced. It later would not fire. I replaced the coils and Power pack, and it runs like a top now. A power pack may explain the motor stalling and loss of power, but wouldn't explain the starter not engaging till it "cooled down" I wouldnt think. You should check all your wiring in your main harness and control box for corroded/loose/pinched wires. You may have a gremlin somewhere. I would especially follow the kill wire (black/yellow) and make sure your battery cables are tight and clean (including wires on starter solenoid). I will be interested to see what others have to say.

[Dhadley]

Alan, since it locked up at wot lets start with the basics. A compression test is a must. Lets get that done before we try anything else.

[Joe Reeves]

Alan.... The engine shut down and wouldn't turn over scenario. That indicates that the powerhead seized due to extreme overheating, especially since you say that after the engine cooled off, it did turn over. This would also indicate that the heat warning horn is inoperatable. Check the horn as follows.Engine not running, just have the key turned to the ON position. At the powerhead, find the TAN wire(s) that is protruding out of the cylinder head(s). Do not disconnect that wire but slide the insulating sleeve back and ground the metal connector to the powerhead. The horn should sound. If it does not, find out why and correct the problem as that warning horn is the only warning you'll receive for an overheating problem.Having a engine overheat to a point whereas it seizes will result in loose head bolts among other items loosening up which may allow some water to enter the cylinders.Compression should be 100+ psi and even on all cylinders. Spark, with the s/plugs removed, should jump a 7/16" gap with a strong blue lightning like flame.... a real SNAP!If the above checks out okay, I'd suspect that the brass fixed high speed jets, located in the bottom center of the float chambers, are still somewhat fouled and rstricted.... causes a fuel restriction, slow pickup, hesitation, stalling, etc.

[CFronzek]

Why did you have to cool it down? Was it overheating? My analysis is unprofessional, but, I would assume it wouldn't crank because it had heated up and siezed. And if it went thru' this process more than once you could have stuck piston rings or worse. If it did sieze several times there's a good chance the pistons have blow-by now. Time to take a compression check. I hope your problems are electrical gremlins as described above but the compression check is mandatory just to rule out internal damage.

[HOUSTON1]

When you say "it didn't even try to turn over" "like the battery was dead" I took it as the starter didn't even try to engage the flywheel. Dhadley and Joe Reeves are both extremely knowledgable, and they have both got me out of pickles with my motor on different occaissons.. You are in good shape in finding what's wrong with these guys helping. My unprofessional take on it was that if it "seized" the starter would at least engage the flywheel, it just wouldn't turn over. Hence why I thought the non-starting issue could be electrical in nature (maybe the kill lanyard or the likes). A compression check is definetly an easy first step, and will give these guys a direction to lead you in..

[Theoutdoorsman]

Now you've gotten my attention, as I have NEVER heard an audible alarm of any kind sound off on the motor. Would be interested in checking other alarms as well, if any. One thing I don't understand, why would it only overheat occasionally? Seems like, if it were a cooling issue, it would do this on every outing. I sometimes take it out twice a week and it would be 2-3 months in between occurences? Oh yeah, new impeller installed at motors purchase. And it "pee's" strong too. I'll check that wire and report back with a compression test ASAP. Stop scaring me..........LOL............Thanks for the quick feedback guys!!! I'll be back with the report......

[Joe Reeves]

If you're in a area where idiots discard plastic bags and the like overboard, you could on ocassion run across one of those bags which would close off the water intake (it happens). Tilting the engine, the bag drops off leaving no indication that there was ever a water restriction. This is one of the reasons that you must have that warning horn system in effect.There are no other warnings pertaining to the 1979 140hp Evinrude, just the overheating one which is a constant sounding.I'd strongly suggest that you drop the lower unit to inspect the water pump assembly. If the engine did overheat to the point of seizing due to a restricted water intake, that impeller will be in pretty bad condition.

[Theoutdoorsman]

I don't have a guage installed to share an accurate water pressure reading, but it appears to "pee" very well. A nice stream of water has always, and still does, come from the motor. I'm on my way to pick up a compression tester right now. I will post tomorrow with the results of that test. I'll start there as suggested and then move foreward with the process of ellimination. Don't get me wrong, I'm NOT trying to be smart. I'm just not very knowlegable in the outboard motor repair field and want to take this slow and soak up watever knowledge you guys can offer. And I thank ALL of you for your time and patience with me. Wish me luck. Will post again very soon.........ALAN

[Dhadley]

You have the right idea. Go slow and take it all in. Youre gettin ready to be exposed to a lot. The compression will tell us if we have a basically sound platform to work with or not. We may have to reconstruct the platform, maybe not.

[mikeyzx2]

Alan, the peeing is only an indicator that the water pump is working. The real issue is whether the thermostat is working correctly or not. After checking compression, you may want to dig into the thermostat housing. It's typically good maintanence to replace the thermostat when water pump is serviced.

[KYHunter]

If I didnt understand your statement, I apologize. I know this, may be, after the fact. You said in your post that the first year . You seldom got above 4500 rpm's. If your motor is anything like my,1978 115 johnson. You really do need to make it a point, to get your rpm's up . I dont know your specs. I know my operating rpm range is much higher then 4500. I run mine at 5300 -5800 rpm's, I think yours should be similar. I rebuilt mine last year. It dropped a piston due to heavy carbon build up. The guy I bought it from said it was a recent rebuild, not so. I only ran it a few times , and kablooey! I hope this isn't your problem. I like my motor so much, I'm rebuilding another one just like it. It is not doing your motor a favor to keep rpm's down , as alot of people seem to believe. Best of luck to you, KYHunter

[Theoutdoorsman]

I do, at times, like to blow the dust out of it. My maximum rpm range at WOT is 5600-5700 rpms. Although, I don't see the need to run 60+ mph on the water everywhere I go......... :-) That's the only reason I don't run it that hard. When I do run it hard, it's usually in short bursts (2-3 miles at best). Hopefully that's enough to burn off any excess carbon build-up. I had a Mercury 115 6 cylinder on the boat before and have found that running the motor at 4500 rpm's produces the same speed as my old motor with a LOT less fuel consumption. Twice as good in fact, if not better. And that's a really great feeling!!! Also, during the break in period, I followed the mechanics instructions to a "T". I ran the motor at no more than 4600 rpm's, varied the rpm range, and ran two tanks of double oil (small 15 gal. fuel cell). Thanks.

[Theoutdoorsman]

ATTN: Dhadley I performed the compression test......and the bad news is.......Looking at the back of the boat forward.The top left....75The bottom left....105The top right....0The bottom right....100 I suppose its off to the mechanic for me huh? At least the motor will still run though....right? Can I perform the neccessary repairs or is this absolutely NOT a good thing for a novice to get into? I do have decent mechanical skills, just not of the outboard variety.... :-) ....I'm not sure I have the proper tools to tackle such a job. That's the only thing that worries me. What do you suppose could have happened? ........I'm sooooooo disapointed.....I tried so hard to take it easy on this motor so it'd last me for good while. Thanks.................ALAN

[Theoutdoorsman]

ATTN: Joe ReevesI checked the audible alarm as you suggested. Both are working. Thanks.......ALAN

[Theoutdoorsman]

I would also like to add that this motor will still run and starts on the first crank. NGK (B7HS 10) plugs were installed in November of last year in my attempt to correct what I THOUGHT might have been wrong. Am I missing something or is it possible for a motor to completely drop a cylinder and still run and start like it does? Makes me wonder if I properly tested that one cylinder. I did it exactly the same for all four. And what about the 75 on the compression test for the top left cylinder..... Does this indicate a possible problem as well?

[reeldutch]

yepi think something is fishy wit the top carburator.both your top cylinders are toast these feed from the top carburator.i suspect you were running lean.the bottem cylinders are probbebly fine but check the carburator anyway.time for rebuild.where do you live?reeldutch

[reeldutch]

i had a friend trowing a rod and he was still able to limp home.those v4s are animals in that way.

[Dhadley]

Go ahead and pop the heads off. They gotta come off sooner or later anyway. Lose the KGB.... errr....NGK plugs.

[Theoutdoorsman]

Attn: ReeldutchWhat plugs would you recommend?Also, both carbs have been serviced by a reputable mechanic recently, and after I noticed that the problem had gotten progressivly worse. He told me afterwards that one of them wasn't set up properly but couldn't remember which one it was. I can only assume it was the top carb. This was most likely the cause of premature internal engine failure though. Wouldn't you agree? Thanks for the advice. Much apprciated..........ALAN

[reeldutch]

plugschampignon Ql77jc4tcw III oilwell its only a big possibility that the top carb was running lean.it would be my first guess after reading your compression chart.if he tells you after he serviced your carburators that 1 carburator isnt "setup" properly, i wouldnt go back to him anymore.you are right most likely.premature i dont think so.it depents on how many service there was done the last 26 years.if the carbs never been overhauled its more logic that it will run lean.may be every 5 / 6 years clean out the carbs its just insurance.pop off the heads and get some pics, like dhadley suggests.may be he can tell you a better story what was going on in the motor.good luck

[reeldutch]

the reason why your motor seized and overheated is because you didnt get enough oil(oil/fuel mix 50:1) into the top cylinders (lean) thats why it overheated. no oil is lots of friction=heatwhy the alarm didnt go off i dont know.you better find that out to.before breaking her in after rebuild.

[Theoutdoorsman]

Are you suggesting I not go back to the mechanic who rebuit the motor, or the carbs. There where two seperate individuals who did work for me. The one who rebuilt the carbs for me had no knowledge of any internal damage. I just asked him to do it to rule out a possibly gummed or otherwise dirty carb. Afterwards, he informed me that the carbs were rather clean but one was set up incorrectly (float I think was way out of spec). Personally, I thought it'd be an electrical problem (power packs and/or coils). Also, I premix my gas and oil at 50:1. Are you suggesting I add a little more for safe measure or would this result in more problems like this later? As to the warning buzzer not sounding at the time of overheating, I'll definitely check into that one. Could it be that the sensors are faulty? I tested both by grounding them out and they worked fine. Are you aware of any other tests that I can perform to check them? Thanks a bunch..........ALAN

[reeldutch]

just by grounding the wires does only tel you that your horn will go off IF your sensor works.you only foun out that your horn is working not the sensors.when you are ready to start rebuilding defently replace them.the mechanic who rebuild the motor in the first place should have rebuild the carbs also.do you know why this motor was rebuild before?might have bin the same problem and the mechanic who rebuid the motor ignored the cause.scored cylinderwalls and broken rings are a result of something wrong with one ore more systems.still the person who rebuild your carbs could have checked your compression after he rebuild the carbs. and run the motor to test.dont add more oil to your gass.you will get a dirty combustion camber wich will result in ring sticking and fouling plugs.if you have it all set correctly the motor will run propper and with some maintenance it wil last for another 26 years.50:1 tcwIII not more not less.ql77jc4 plugs gapped 0.30/0.40you might want to do a decarb every 50 hours.to ceep it carbon clean.have you taken the heads off yet.thats your first concern right now.good luck

[Theoutdoorsman]

No, I haven't popped the heads off as of yet. To be honest with you, I've never popped the heads of anything before, but I'm going to give it a go. I just recieved my service manual yesterday and I have to begin working again today. It's going to be 4 days before I can begin, and it will likely take me some time to do so, but I intend to do it ASAP. I'll post again with some photo's once the job is done. Unless, that is, you think this would be a job better suited for a marine mechanic. Be patient as it may be a few days before I can get back to you. Thanks...........ALAN