'84 Evinrude 115hp Loss of Power

'83Crestliner

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Oct 12, 2010
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39
Hey All. I am new to this game and have much to learn! I recently bought a Crestliner and it has an '84 Evinrude 115 on it. The motor is pretty clean, compressions are 115 - 120 on all, and i just replaced the spark plugs from the old ones it had (wrong ones at that). I have taken the boat out a couple of times now and everything runs great for about the first 30 - 40mins and then i get a segnificant loss of power. The motor starts to sound rough, and it tries to get through it, but it cannot. It seems like if you cut the motor for a bit (30mins +) it comes back strong, but only for a short period then hesitates and so on. The motor will even start to vabrate the boat bad, thats how rough the running can get on it. I have looked at some of the posts already made to see if i could pin point something, but have not seen that similar of a situation. Is this a Ignition Package issue?

Thanks!
 

RJ17

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Sep 29, 2010
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Re: '84 Evinrude 115hp Loss of Power

I don't have an answer for you but I have an '89 140 hp Evinrude on a boat that I purchased 2 weeks ago. This weekend I had power issues similar but perhaps unrelated to yours. My engine would vary in RPMs, some times dropping without a shift in the throttle, sometimes over revving without any increase in thrust. When the RPMs dropped thrust would drop too. When over revving thrust did not change or dropped some. Not sure if this is fuel issue, a lower unit issue or what. Hope it isn't an Evinrude issue!
 

emdsapmgr

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Re: '84 Evinrude 115hp Loss of Power

It's either fuel or spark. I'd check for spark first. Easy to check to see if you have good spark or not. Run the engine till it starts to act up. When the engine starts to miss, put an inductive timing light on each plugwire and see if it is sparking, missing, or weak spark. That engine has two power packs, each controlling the spark to the pair of spark plugs on one bank of cylinders. You can swap the power packs and the ignition coils to see if the problem moves with the exhanged ignition part. Weak ignition components tend to fail once the engine heats up to normal operating temperature. Your compression is very good.
 

'83Crestliner

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Re: '84 Evinrude 115hp Loss of Power

Thanks for the guidence "emdsapmgr"

I will check it out and see what i find. As far as the fuel issue, would it just be a matter of inproper gas/oil ratio or improper mixing? The first time i took it out i did not do a good mixing job, and i did have this power loss problem. Although, i took out two other times and did mix it well. Having put properly mixed fuel in after the first time of doing it poorly should erase that potential issue?

RJ17, It sounds like we have a similar problem.
i think Evinrude is a pretty good motor. I know a couple of people who swear by them. I may not have picked it personally, but it is the original motor that came with the Crestliner that i have. The boat has an hrs meter and it reads that the motor only has 246 hrs on it. I am skeptical, that meter could have been tampered with.

I did hear something scary though. I talked to a mechanic that works at a local boat sales and service place and gave him the highlights of my issue. He told me that if i was getting about an hour of the motor running well i was doing pretty good. I did not like that, at all.

Is that how it goes sometime with outboards in general emdsapmgr?

thanks again for the feed back guys.
 

emdsapmgr

Supreme Mariner
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Re: '84 Evinrude 115hp Loss of Power

If you keep the maintenance up on any outboard, it will give you good service. It may take you a little time to get your maintenance up to date on your new purchase. I wouldn't get too frustrated yet-you may be living with a problem the prior owner didn't fix. Oil/fuel mixtures are extremely important on 2 stroke outboards. Running with too little oil at high rpm's for a long time can be a problem. Your engine originally came with a fuel pump that would automatically mix the correct oil with the fuel prior to delivery to the carbs. Perhaps it has been replaced with the simple (old style) inexpensive premix pump. In any event, you need to be sure the engine gets the right oil mixture into the carbs for long-term durability.
 

archcycle

Chief Petty Officer
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Sep 21, 2009
Messages
647
Re: '84 Evinrude 115hp Loss of Power

Agree with the earlier poster on losing power after ignition parts heating up. I had a very similar problem and traced it down to the ignition coils and bad connections on wire splices between the powerpack and the coils.

Pull off the coils and see if the backs of them are cracking (it's glue'ish stuff). If they're cracked up and dried you probably need to replace them. They're around $25 each, and just all around probably not a bad thing to replace on an older motor anyway.

The fact that you can let it rest a while and then run it again fine really points to something overheating, and between a fuel system component having a problem from heat and an electrical system with a problem from heat, I'd start with the electrical.

Unfortunately the only way to really test the coils (because you need them testing while you are having a problem, not in the driveway) is with a peak reading voltmeter which will cost you way more than a few new coils.
 

'83Crestliner

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Re: '84 Evinrude 115hp Loss of Power

emdsapmgr, you are exactly right. The previous owner did disconnect the auto oil mixture, to just doing it manually. He did not tell me he was having any issues, he just told me that he never trusted that it was do the job properly. I have heard of a many people disconnecting the auto oil mixing, i wonder why that is? There must be some sort of consistent theme that makes people do it. If it is working fine, why mess with it.

archcycle, i agree with what your saying. I will be checking all those connections out to see whats going wrong.

thanks for the feedback!
 

boobie

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Re: '84 Evinrude 115hp Loss of Power

That mechanic that told you about 1 hr of good running should either go back to school or get out of the business.
 

RJ17

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Re: '84 Evinrude 115hp Loss of Power

OK, so I was out again this weekend, in relatively heavy seas (2-3 foot rollers and some chop on top with the occaisional 5 footer). The engine performed fine at about 2700 RPM, maintaining a 7-8 MPH pace (per my GPS) into the waves and wind, riding nicely over and through the waves. When I got into the lee of a peninsula I got the speed up to 27-30 MPH at around 4500 RPM. All good so far, right?

I should mention that I fueled with fresh gas from a gas station while the boat was on the trailer (16 gals in a 35+ gallon tank). I also warmed the engine up at no wake speed for about 10 minutes, after idling at the dock for about 3 minutes.

I turned to head back with the now following sea. "Surfed" one or two rollers nicely and maintained 8-10 MPH for a few minutes. Opened up the throttle and began to climb to 20+ MPH. The engine would essentially die. Thrust would be dropping and eventually almost die completely. I had to move the control back to neutral and then forward to regain any speed. Just advancing the throttle when power began to drop did no good. If I move the control to idle the engine died completely.

I suspect one of two culprits (or both). 1st thought is the fuel system/line. I was "jumping" off the tops of some waves and landing in the trough pretty hard. The power issue developed after/when I was doing this (though it did not occur when I was heading into the waves, only in the following sea). I checked the bulb on my fuel line when I was losing power and it was "soft". I squeezed it until it was "hard", assuming that fuel was not reaching the motor. Generally I was squeezing the bulb after the power loss issue occurred but i did try it once or twice while the motor was losing power and saw no improvement.

My second suspect is the throttle itself. It is an OMC and I presume original equipment (1989 boat, 1989 Evinrude 140hp). The throttle is a bit quirky in that it seems like it jumps the power from 2500 RPMs to 4500 with very little travel. Part of the jump could be the boat moving up on plane with that little bit of extra power and so RPMS jump because of less resistance. I even when I get up to speed (say 28-30 MPH and try to eas back just a bit on the control to see if I can get to say 15 MPH the motor slows considerably and I drop off plane to 10 MPH or less, again with only minimal travel of the shift. Further, the control arm "pops out" from the mount to put the motor in neutral so that it can be revved or started in fast idle. The prior owner explained to me that once the motor has been running it can be difficult to start in neutral without "popping" the arm out to full neutral position, shifted all the way (to both forward and reverse) and then placed in idle or fast idle postion for starting.

I am thinking that I need to monkey around with (or replace) the control and/or the fuel line.

Any thoughts any one?
 

emdsapmgr

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Re: '84 Evinrude 115hp Loss of Power

You could temporarily test the fuel system by taking a spare 6 gallon fuel tank with you. When you have firing issues, plug this test tank in and see what happens. I'd also use another fuel line for that test. It is possible that you need to adjust the shift and throttle cables back at the engine end. When the control boxes act up, it is usually due to slight misalignment of the cables. Have you checked the spark yet?
 

RJ17

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Re: '84 Evinrude 115hp Loss of Power

I have not checked the spark. I am just assuming that the plugs are OK and firing properly since the motor runs just fine until this issue crops up. The spare tank idea is a good one although the current fuel line appears to me to be "permanently" connected at the engine. By that I mean that there is no plug/rapid connector that I could just detach and then snap in a new line from a spare tank.

The throttle/shift cable idea has me interested. I presume that just removing the cover and moving the shift will show me how the cables are operating. From that inspection I can check that all of the moving parts are properly connected and won't/don't get loose or slip due to vibration.

Thanks for the ideas.
 

'83Crestliner

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Re: '84 Evinrude 115hp Loss of Power

I am still struggling with my power loss issue,but i think i have pin pointed the problem. Having checked spark, and looked over ignition parts everything looks good. I took the boat out to test the possible fuel issue and found that when i had a loss of power if i had my friend pump the fuel line power would come back, and the motor would sound good again. This would only regain proper power for a couple of minutes and then the power would drop again. I also tried to press the primer/choke with the key and this also made a positive impact on the proformance, but for an even shorter period of time as pumping the fuel line.

If my power loss problem is coming from not enough fuel getting to the motor, is this a simple issue? Is there an obvious answer or replacement part for my problem?

Thanks.
 

emdsapmgr

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Re: '84 Evinrude 115hp Loss of Power

If the engine runs ok when you constantly prime the fuel hose bulb, it is likely the fuel pump is weak. If it will run fine when you constantly prime the bulb, likely the fuel lines and fittings are not restricted and are OK. The pump can't supply enough fuel to keep up with the needs of the carbs. If you prime the fuel hose bulb, that will fill the carbs. As you continue to run, the fuel level in the carbs slowly decreases, and eventually you start to run lean again. Pushing in on the choke will help, till the choke runs out of fuel. That engine probably came with a VRO type pump-a really expensive replacement part today. It will be worth your efforts to do some testing of the system to make sure the pump is the real culprit. The factory service manual has some tests for that pump, including a vacuum test. You might want to consider converting your engine to the older style (premix) fuel pump, which would be significantly cheaper.
 

'83Crestliner

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Re: '84 Evinrude 115hp Loss of Power

Yea. When i start running all is good for about 30-45 mins. and then i get the power loss issue. You are exactly right it is V4 VRO, but the auto oil mix has already been converted to the old style pre-mix set up. That being the case, do you see the fuel pump as being the problem? The fuel hose bulb is what i am pumping to re-gain the power.

Is a new fuel pump something very difficult to change myself? If that is the issue, just wondering what kind of cost i may be looking at.

Thanks so much for the feedback.
 

emdsapmgr

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Re: '84 Evinrude 115hp Loss of Power

I'm concerned that the engine runs fine for the first 30-40 minutes. If the fuel pump were weak, you would notice that the first time the engine got to full throttle. The fact that it takes this long to start acting up would make me think you have some weak ignition component which acts up once the engine reaches normal operating temps. Replacing that old style (premix) fuel pump is not a difficult chore, nor is it very expensive. (About $100-the pump 438556 is currently on national backorder. However, there are many, many dealers across the country which have stock on this part.)
 

RJ17

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Re: '84 Evinrude 115hp Loss of Power

I, too, am suspecting fuel system issues. I went out yesterday and made two changes. 1st I added SEAFOAM to the fuel (about 1 ounce per gallon) to try and clean out the system, especially the carb. 2nd I used mid grade (89 Octane) gas instead of regular (87).

The engine started fine but seemed to "skip" at around 3100 RPMs. Could not get it past 320 RPM when in gear, could not get on plane, max speed 7-9 MPH. Often stalled out when brought to idle. After and hour or so (and removal and cleaning of the plugs with a dry rag) I started back up and could get to7000 RPM with no skip! (Don't panic, just in idle and only for a second or two). Would idle for as long as I wanted at 3, 4 or 5000 RPMs.

When I put it in gear I got full power (at about 4500 RPM) and could reach 31 MPH. As soon as the boat started to bounce at all from going over waves (either into or with a following sea and waves were small, 1-2 ft) engine would lose power and ultimately stall out.

While I haven't ruled out throttle issues fully sure seems like fuel relate to me. I, too, have a V4 VRO (140 hp).
 

Rudy Brown

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Messages
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Re: '84 Evinrude 115hp Loss of Power

RJ, please dont rev that motor in neutral. 2 cycle motors can over-rev easy and blow up.
One another note, make sure all the ground connections on the power packs are tight. I still believe you have a fuel problem. I once had a problem like yours, turns out that a small piece of cellofane was in the tank and would suck up to the pickup starving the motor. Took forever to figure that one out.
 

emdsapmgr

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Re: '84 Evinrude 115hp Loss of Power

You need to verify that you have solid spark to all 4 plugwires when the engine starts to act up before you invest in a new fuel pump.
 

RJ17

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Re: '84 Evinrude 115hp Loss of Power

RJ, please dont rev that motor in neutral. 2 cycle motors can over-rev easy and blow up.
One another note, make sure all the ground connections on the power packs are tight. I still believe you have a fuel problem. I once had a problem like yours, turns out that a small piece of cellofane was in the tank and would suck up to the pickup starving the motor. Took forever to figure that one out.

Can't imagine the time, effort and frustration to figure out the cellophane issue. About the only thing I can think of there is to pump the tank dry and then (somehow) try to clean it out fully.

As for over revving I only let it go there a few times and only for a second or two. I began to throttle back as soon as the Rams climbed over 5000.

Thanks
 

RJ17

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Re: '84 Evinrude 115hp Loss of Power

You need to verify that you have solid spark to all 4 plugwires when the engine starts to act up before you invest in a new fuel pump.

I think I am going to try and investigate fuel line:tank issues before I look at the pump.

I am curious, and a neophyte, regarding the electrical side of things. This engine had the power pack replaced in August. I am operating under the assumption that since it runs fine in idle and since it can get up to a normal operating range for both RPM and M PH that the sparks are firing fine. My guess is that the cylinders are. Either starved for fuel or are getting too lean/rich a mix (or maybe even too .such oil) and hence the power drop and then stall.

Any comment on the impact of reverse blowing the lines on the bulb?


Thanks for your help.
 
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