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1977 140 hp Evinrude, no power, won't get up on plane

S

stingerbassboat

Member
Good morning guys, I'm back with my 1977 140 hp evinrude problem. Here's everything I have done or had done to this engine. It starts, idles a little rough but the motor always has. The problem now is the motor sounds great at full throttle, only problem is, not enough power to get the boat up on plane. I have to stand on the front of the boat while my brother drives to get it to get up on plane after a couple 1,000 yards it finally will get up on plane. Engine sounds great, no mis fires or even sounds like it's struggling to run, just doesn't have enough power. Here's what all that has been done and I'm just at the end of my rope with the motor. I have owned the boat for 12 years now and not one single problem until this problem. New fuel pump, tried a new electric fuel pump, all lines from tank to carb replaced, new bubble, bypassed the fuel connector at the motor, new plugs (2 times), New timing base plate, new stator, new crank seals, all 4 new coils, new power pack, compression on all cylinders between 105 and 112 psi, I have gone thru the entire wire harness from control box to motor, no broken, bare or loose wires, visually checked all wires on the motor, cleaned connections at block and power pack, all linkages has been checked several times. When throttle from control box is wide open, carb butterflies are wide open and sitting on the pin stop as far as it can go. The motor states to set the timing at 28 degress, I've tried that but I was told by a local marine mechanic to set it at 20 degress, which it does run better at 20 degress. I bought a new CDI timing base plate which looks nothing like my old one but the mechanic confirmed it is the right one for my motor. For some reason tho, it runs better with my old one but I've switched them back and forth everytime I replace something else on the motor. If the cover is off the motor, it will die when trying to apply the throttle, I assume, it sucking too much air with it off. I've been convinced all along it's simply not getting enough fuel, O yes, carbs rebuilt by a local marine shop but checked and cleaned 2 times before I just had them rebuilt. He said he found a little grit inside but nothing else wrong with the carbs. I am at my end with this motor but feel I'm so close to getting it right. It runs fantastic at full throttle just no where near the power this engine used to have. Please, any help would be much appreciated, I've spent well over $1,500 on this engine, not including labor cost. The problems before were not the same as now. All this started because I ran the boat for maybe a 1/4 mile wide open and it just shut off like you had turned the switch off. No longer doing that but has no power......Danny
 
Compression is very suspect here.----In good condition they run really smooth !!!----Remove bypass covers and inspect pistons and rings.---Costs you 4 cheap gaskets if nothing is wrong there.-----I say you have broken piston rings.-----A very common problem on those V-4 motors.
 
According to the manual, if it's anything above 100psi, it should be good, just going by that and the compression was checked in 2 different shops the boat was in earlier this year. I'm certainly not boat motor expert by any means, I can rebuild any V-8 engine in my sleep but for the life of me, I can't convince myself a motor would run this smooth, quiet, no smoke and have cracked or broken rings. It's hard to describe just how good this motor runs at half power. Once up on plane, you couldn't ask for a motor to run any smoother and with a load on it, full throttle coming out of the hole, it sounds perfect. Is it possible with that description to be bad rings and that 2 shops missed it when checking compression. Remember, it started by shutting down like you turned off the switch. Symptoms have changed as I've replaced parts to this now problem of a lack of power. I know by it not running as good with the hood off that the fuel air mixture can't be right and that for some reason, it just doesn't seem to be getting enough fuel to run full power. I do have to tilt the motor up more than usually when I get up on plane for it to push the boat fast, normally my motor is tilted almost all the way down when up on plane to keep the nose down but honestly, that engine sounds perfect when running at full throttle, better than it used to if that makes any sense. I guess with all the new parts is why it sounds better now. I used to get it up on plane and then back off the throttle, that's about exactly where it used to run on plane before, I just can't tilt the motor because it struggles with the lose of power. Thanks for responding and I'm not questioning any help, I'm just trying not to go down the wrong path for weeks like before only to have the same problem. I don't have another shop near me that will work on a 77 motor, if it's going to get fixed, me and my brother have to do it or just give up and buy another motor or boat.....Danny
 
Well -----100 PSI on one of those is no good.----It is a 2 stroke and has to smoke.--------So I will step aside until you do some real trouble shooting !!!-----It only sounds ---" perfect "----To the untrained ear.
 
I understand that and don't mean to question you but untrained is far from the truth. I've been an ASE certified mechanic for 30 plus years. While I understand the components that make a 2 stroke run are much different than say a gasoline or diesel car motor, the controlled combustion within a cylinder that makes them run, is no difference. Fuel, spark and air inside the cylinders is the same on all controlled combustion engines. I was only stating that I've dealt with cracked or broken rings many many times, inside the cylinder of a controlled combustion engine, will be no different as far as the symptons it will produce. I understand these are designed to burn oil thru the fuel mixture but how could I not see excessive smoke if the rings are allowing the combustion to enter the crank case? How could an engine not sound different on exhaust if some of the combustion was seeping by the rings. How could the engine not be taking on raw fuel into the crank case if the fuel enters the cylinder before it fires at TDC. As I asked, is it possible for a 2 stroke engine to have broken or cracked rings and not show any signs other than low power. Of course it will effect the power if they are but shouldn't there be other symptoms they also say it's the rings, I'm just asking because broken or cracked rings on a gasoline or diesel engine will lack in power but will certainly show other signs to point to bad rings. I'm semi retired now but for 25 years, I trouble shot the OBDII system in automobiles for ITT who developed the OBDII system. I am somewhat embarrased that I solved many problems that dealers couldn't solve on their own vehicles but can't figure out why a 4 cylinder engine seems to run perfect but have half the power. Hope I didn't offend you and I do appreciate the input. As of right now, we have spent 2,000 on this motor following advice from those who do know much more than me on 2 stroke engines. As you can imagine, it's frustrating and I don't mind one bit tearing this motor down and putting new rings in it, I just don't want to open the motor unless I'm sure that's what it is. Regardless of the PSI in the cylinders, what's the odds all 45 cylinders have cracked rings, shouldn't one cylinder have much lower PSI than the others if the rings are bad? There just doesn't seem to be enough symptons when taking the matter as a whole to say, the rings are bad. Thanks for responding, if I knew what the problem was, I wouldn't be on here, right...LOL....Danny
 
I was just hoping someone out there has been down this same road and shares what fixed there motor. I've heard at least 6 different owners who experienced the shutting down problem and what fixed the motor. I've replaced all that but it hasn't fixed mine.
 
What are the RPMs when you get it wide open?
Is it possible your boat has taken on a lot of water, or something else weighing a lot?

Jim
 
Jim, rpms are around 3500 sometimes closer to 4000, I pull my drain plug after I take it off the lake every time. It's always taken on a small amount of water, maybe one of the live wells has a leak, never enough for me to be concerned about and I like it doing that so it keeps the hull washed out. I've just always watched the amount it drains, so if it ever got worse, I'd need to find where it comes in. I'd guess never more than a gallon of water drains out, takes about 10 seconds for all of it to drain out...Danny...Good point tho, I never thought about that and taking on a lot of water would certainly make it hard getting it up on plane, thanks....Danny
 
So you spent hundreds of dollars on parts and replaced the crank seals. And yet refuse to to spend $50 on head gaskets. And there is no factory OMC manual that I know of that tells you anything above 100 psi is good. And to top that off you are changing the timing on a crossflow motor, How can that go wrong? . Maybe get a factory manual and a set of head gaskets and start from there. And when you get the manual start on page 1. No mention of a proper spark test and really don't think sucking to much air is a thing.
 
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Well, I do appreciate you guys input. I stand corrected on the psi, not sure where I got what I got but I stopped by the marine shop yesterday to pick up a crank flywheel shear pin where I forgot to torque the bolt back down. Mike pulled the record up for me where he ha done work on the motor and showed me where the psi on the cylinders were all between 121 and 126. He said that he had told me that some manuals say above 100 is good, I guess that's where I got it. Give me a break guys, I've had this boat in 2 shops for the past 8 months, after a while, everything said to me just runs together. He absolutely assured me, there is nothing wrong internal on this motor. Mike stopped working on the motor because he just couldn't spend anymore time trouble shooting it with 25 other boat owners breathing down his neck. He done hours of work and received nothing for his labor because he didn't fix the problem. He told me if I couldn't fix it, bring it back in November or December when he wasn't as busy and he would try again. Your right, $50 is nothing compared to what I've spent but it's a lot easier to say, try it than someone like me who doesn't work on these motors to do it. Anybody can throw darts at a problem if they don't have to do the work. I ask you to remember what the problem started as, after 1/4 mile wide open, it shut down on me like you turned off the switch. After it would do that, not enough power to get up on plane.
 
Likely not issue but did you check gap on plugs?

When you say you set timing, did you do so following OMC manual or did you wing it? With all that you describe it sounds like a well running motor that just may not be igniting at the ideal time for max power. Also, you did not mention that you set idle timing - was that done also again following manual? That might account for the rough idle.
 
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It's had 2 new sets of plugs put in it. These type plugs don't have a gap, they are flat on the bottom. The motor says 28 degrees is what the timing is suppose to be, big black letters right on the motor. But, I was told to set it at 20 degrees. Before I set it at 20 degrees, the motor would die as soon as you put it in gear, setting it at 20 degrees has been what has allowed me to at least move forward without it dying. While the boat is up on plane, I've adjusted the timing as much as 10 turn out and 10 turns in, it really doesn't effect the power loss at all, all that does is prevent the motor from even trying to run if it's not at or around 20 degrees. I've swapped my old one with the new one every time I put something new on the motor and like I was saying, it seems to run better with my old one on it than the new CDI timing base plate. The motor at adle has always been a little rough to me, I was told it's pretty common on these older motors and it's not real bad, doesn't die, just idles what I call rough, meaning the motor shakes a little at idle. I can idle it up using my fast idle lever and with a little higher idle, it smooths back out. I think I can get it to idle a little better once I figure this loss of power problem out. I use a timing light at 3500 to 4000 RPMS to set the timing on the motor, least that was what I was told by a mechanic to do, had to download a RPM app on my phone to accomplish that at the lake.
 
Fact-------The maximum timing advance is set at the factory ( 28 degrees ) and generally does not need adjusting for the life of the motor.------Then there is idle timing and it looks after itself.------Then there is timing for throttle plate opening.-----If you start adjusting timing with the ---" i wonder what will happen if I move this "---- approach you can damage the motor.-----Sorry to be so blunt here.
 
Flying Scott, if your not going to help, just be gone my friend. I think you have plainly stated, a 2 stroke engine is not the same as a V-8 gasoline engine. 1st, you only have 4 cylinders not 8, second, you could adjust the timing on a 2 stroke engine as far one way as the other and it will still run. Timing on the 2 stroke effects the quick start and the top end power/speed the motor has. You can't get a 2 stroke 180 degrees out of time but you can get a V-8 180 degrees out of time. Is that enough difference for you? Your being rude because I ask more questions and you don't seem to like that but you also don't read very well. Go back to my first post and explain to me how an engine just simply shuts off because the rings are cracked or damaged. Heck, I've driven a vehicle with a hole in the top of the piston, still ran but sounded like crap. There's not a combustion engine on the face of this earth that would shut down like you turned off the switch because the rings are cracked. 2 certified mechanic shops in my area have had this boat for over 8 months, don't you think if it was as simple as the rings, they would have diagnosed that very quickly. Both checked compression and told me it was fine, what should I do, call them a liar? I appreciate any help but I can go anywhere and be insulted, just move on and find someone else to argue with. In fact, you said you were stepping aside but that would be too easy and you wouldn't get to insult me if you done that. These other guys are asking questions and I'm answering them the best I can. If you don't want to help, it's fine, just don't use space on my post to insult me. You have a blessed day...Now, to answer your questions, I don't take the adjust attitude, I take advice from mechanics who tell me what to do, what else can I do? Both shops adjusted the timing, adling and linkages on the motor. Both shops took the motor to the lake and it done the same thing. I haven't messed with it since I got it back from Mike other than switching out the CDI and my old one. One would assume, either should be the same due to the linkages, you can only hook the one linkage up to the timing base plate one way unless you adjust it. I have checked the timing 2 times and it's the same with either timing plate. As for the 28 degrees, all I can tell you is since I moved it to the 20 degrees like Mike told me to do, the boat runs, it will not take one ounce of fuel at 28 degrees, the motor dies as soon as you put the motor in gear. I tried munipulating the carb by hand and as soon as you crack the butterflies, the motor dies. As stated before, the carbs have been completely rebuild and the reed valves were fine.
 
Timing needs to advance BEFORE you can open throttle plates.----If timing does not advance the motor will die on you !-----This 2 stroke is a different machine than ---" grandpa's 283 Chevy "
 
stingerbassboat said:
Flying Scott, if your not going to help, just be gone my friend. I think you have plainly stated, a 2 stroke engine is not the same as a V-8 gasoline engine. 1st, you only have 4 cylinders not 8, second, you could adjust the timing on a 2 stroke engine as far one way as the other and it will still run. Timing on the 2 stroke effects the quick start and the top end power/speed the motor has. You can't get a 2 stroke 180 degrees out of time but you can get a V-8 180 degrees out of time. Is that enough difference for you? Your being rude because I ask more questions and you don't seem to like that but you also don't read very well. Go back to my first post and explain to me how an engine just simply shuts off because the rings are cracked or damaged. Heck, I've driven a vehicle with a hole in the top of the piston, still ran but sounded like crap. There's not a combustion engine on the face of this earth that would shut down like you turned off the switch because the rings are cracked. 2 certified mechanic shops in my area have had this boat for over 8 months, don't you think if it was as simple as the rings, they would have diagnosed that very quickly. Both checked compression and told me it was fine, what should I do, call them a liar? I appreciate any help but I can go anywhere and be insulted, just move on and find someone else to argue with. In fact, you said you were stepping aside but that would be too easy and you wouldn't get to insult me if you done that. These other guys are asking questions and I'm answering them the best I can. If you don't want to help, it's fine, just don't use space on my post to insult me. You have a blessed day...Now, to answer your questions, I don't take the adjust attitude, I take advice from mechanics who tell me what to do, what else can I do? Both shops adjusted the timing, adling and linkages on the motor. Both shops took the motor to the lake and it done the same thing. I haven't messed with it since I got it back from Mike other than switching out the CDI and my old one. One would assume, either should be the same due to the linkages, you can only hook the one linkage up to the timing base plate one way unless you adjust it. I have checked the timing 2 times and it's the same with either timing plate. As for the 28 degrees, all I can tell you is since I moved it to the 20 degrees like Mike told me to do, the boat runs, it will not take one ounce of fuel at 28 degrees, the motor dies as soon as you put the motor in gear. I tried munipulating the carb by hand and as soon as you crack the butterflies, the motor dies. As stated before, the carbs have been completely rebuild and the reed valves were fine.
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You have no idea how timing on that outboard works. You have stuck hundreds of dollars of parts at and it still doesn't run right. You refuse to listen to anything people tell. You refuse to buy a factory Manual. Good luck with your motor you know everything I am sure you will have it running lickety split.
 
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I went back and read the other original thread.
Nowhere did I read that you checked spark WITH A SPARK TESTER yourself.
I did see where you mentioned you checked spark at the plugs.
Have you checked it with an open air tester?
You really do need the factory manual. I have one for every engine, and this website sells them.
EBAY is good too if you want an original one.
https://www.ebay.com/itm/255098999737?hash=item3b6515d3b9:g:CEIAAOSwg-ZhHZO1

One of the toughest problems in repair is replacing a bad part with another bad part.
Doesn't happen often, but when it does.....OUCH!
This may have happened to you.
My mind keeps sticking at the 3500-4000 RPMs. That seems way low, like it isn't running on all cylinders.
Shouldn't it be 4500 to 5500?

Jim
 
Yes, wide open it would be 4500 to 5500 but the mechanic told me to set the timing at 20 degrees at 3500 to 4000 rpms. I really don't understand that because the adjuster for the timing plate is a stop, if it's set at 3500 to 4000 rpms at 20 degrees, I don't understand how it can advance any further to allow the 4500 to 5500 rpms. I was telling my brother just today, I'm wondering the same thing as you. Is my old timing base plate bad and unfortunately, the new one is also bad. Seems unlikely but it just seems to me it's not advancing the timing as far as it needs to when you open the throttle. I'm now convinced 100% it's not a fuel supply problem. Everything from the tank to the carbs has either been replaced or rebuilt. I have observed the timing advance as the engine is running and at full throttle, it advances the timing until the adjust rubber stop and it can't go any further than than since thats where I set the timing at 20 degrees. Next time at the lake, I'm going to set the timing at 28 degrees, which I already know, it won't even go in gear, it just dies. Then I'm going to put the new CDI timing plate on it and make sure it's at 28 degrees and see if it acts the same. Least then I'll know, I either have 2 good timing base plates, or 2 bad ones...thanks
 
WoW. You have no CLUE about 2 strks and your Mechanics are suspect. Full Timing (28 deg) stops advancing around 3500 rpm on your 2 strk. That means you have full advance around 3500 rpm which is the way it should be. I know you won't listen to me but may you SHOULD BUY THE MANUAL!!!!!!!!!!!
 
Was thinking about this today, is it possible that you have a worn throttle cable that isn’t taking th carb to WOT? Have you visually checked to make sure carb butterfly ends up horizontal at full throttle?
 
One more thing your motor does not have qwik start. And qwik start affects the timing your timing does not effect qwik start. I am being rude because you don't listen.
 
Yes I have checked the throttle cable, I have had my brother just put in barely in gear and I have physically work the carb by hand. The butterfly arm that holds them on and extends out the side of the carb has a pin stop, the pin stop when working the throttle at the dear box, is all the way against the stop. I'm also going to eliminate the fuel system completely next time I go to the lake, I'm making me a one gallon fuel tank I can put on my seat that's well above the motor and connect it directly to the carb lines after the fuel pump to gravity feed the carbs. If it doesn't change anything, at least I can eliminate anything from the fuel pump all the way back to the tank. I done this just after the tank one time to see if the pickup stem inside the tank was broken or clogged and it didn't make any difference. Not sure why I still feel the need to do this but don't you think that should eliminate anything with the fuel supply doing that. I used to do that on automobiles I've restored when I thought there might be rust in the tank or a clog somewhere in a line or connection.
 
After what I've already done to the fuel supply, I'm pretty well convinced now, it is something to do with the timing, I just don't know what else to do to fix it or confirm it's the timing. When I'm setting the timing and adjusting the screw, the timing mark moves as it should. I also have my snap on tools spark tester hooked up to the plug wires, changing from one to another when it's running and I don't see anything wrong with the firing of the coils, both in OHMS and the order they are firing. I've checked the spark before by putting plug gaps between the plugs and the unplugged wires to physically observe the spark going to the plugs and all 4 jump a 3 inch gap to continue firing the plugs. It's also had 2 different power packs, thought I got a bad the 1st time but obviously not.
 
One more question guys. From what I can read, the reed valves prevent air and fuel from coming back into the carb. Is it possible for the reed valves to be bad and not get some fuel feeding back thru the carbs? I don't see any signs of fuel coming out anywhere from the carbs but I can see why this could be my problem since air would also escape back and not create the vacuum it needs to pull more fuel into the crank case? The 1st mechanic had written on the bill that he inspected the reed valves, I just took him at his word but I can certainly see how sticky, broken or poor sealed reed valves could be the problem. I was just wondering if they could still be bad if fuel wasn't coming back thru the carbs. If any of them are actually stuck closed, I could see how fuel wouldn't be able to come back thru and how more fuel wouldn't be able to be feed to the pistons...thanks
 
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