Evinrude 1995 40hp running bad on full trottle

[oldboat1]

It sounds OK to me. You're running on muffs and in neutral. Have you tried it in gear and in the water?

 

[racerone]

When the motor is idling " perfect " pull one plug wire off.-----------What happens ?------Then pull the other one off.--What happens ?

 

[Tommyaleks]

It sounds OK to me. You're running on muffs and in neutral. Have you tried it in gear and in the water?

On the video it`s on muffs but I have changed that now so now it is a big water bucket. it is no different in high rpm without or with muffs. No not in gear. Shall I try it in gear? with or without cables? I don`t have the cables connected now. Sounded ok to you? even in high Rpm?

 

[oldboat1]

Yes, sounds OK to me. Racerone is suggesting it may be running on one cylinder (to check, would pull off plug wires one at a time). If you disable a plug but get no change in operation (rpm change, for example), that plug probably isn't firing. Sound doesn't tell the tale, so should do the test suggested.

You can't safely run at high rpms unless you have a test wheel or are on a boat in the lake. Short bursts maybe, if in a big barrel. You can test shifting in and out of gear, though. (Back pressure is important for testing -- can't get that on muffs.) Can test without the cables connected, unless you need to test cable and box operation as well.

 

[Tommyaleks]

Ah ok. But it did not sound like it goes only on one cylinder tho. but I will test it. The problem with that test is that you can only test that on idle, if there is changes in rpm on idle the spark plug is ok but that does not mean it can`t cut higher up in rpm. I agree with you there, it`s dangerous to test it with a propeller with high rpm in a bucket, I see that. The other engine`s I had was tested in a bucket on high rpm and one of them had a ignition issue that was fixed. no lake for testing and no propeller going. You can hear if an engine is no good and it can be fixed. even in a bucket on a stand. if I can get this engine to run normal from zero to full rpm without any problem (short burst like you say) I would be happy. then I can test om a lake. but this engine is not feeling well at all, there is no reason to take it on lake yet. I would only end up with lot`s of paddling lol.

But before I can test the spark plugs and so on, I have to fix the reeds that is on my table. I will do that tomorrow.

 

[racerone]

You have stated that it runs " perfect " at idle.----To me that means there is no problem with the reed valves.

 

[Tommyaleks]

I agree with you on the idle but it also have something to do with the higher rpm`s. I will explain. on low idle there is not so much back pressure as there is at higher rpm`s there for the engine will idle fine (if they are not broken or cracked) and you will have no blow outs in the carb. But as soon you are hitting the gas and get to a higher rpm the pressure are much higher. when the flaps go back they have to be tight flat on the cage, if they don`t, you will have blow outs through the carbs on the return and you will also have fuel leftovers in the chamber. to much fuel means your rpm will be weak and will have less power and so on. I did see light ( openings) in the reed cage between cage and flaps. That could be the problem, this is the only thing I have not tried yet. after lot`s of reading after a tip from a guy, I took them out to see if they was ok. and after some more reading I also found out that they have to be total closed to work 100%.

 

[racerone]

Good luck with the project.

 

[flyingscott]

I agree with you on the idle but it also have something to do with the higher rpm`s. I will explain. on low idle there is not so much back pressure as there is at higher rpm`s there for the engine will idle fine (if they are not broken or cracked) and you will have no blow outs in the carb. But as soon you are hitting the gas and get to a higher rpm the pressure are much higher. when the flaps go back they have to be tight flat on the cage, if they don`t, you will have blow outs through the carbs on the return and you will also have fuel leftovers in the chamber. to much fuel means your rpm will be weak and will have less power and so on. I did see light ( openings) in the reed cage between cage and flaps. That could be the problem, this is the only thing I have not tried yet. after lot`s of reading after a tip from a guy, I took them out to see if they was ok. and after some more reading I also found out that they have to be total closed to work 100%.

That is not right. There is less pressure on the reeds when the motor is idling than at WOT. So a reed problem will show up right away at an idle.

Your reeds are fine do the cylinder drop test.
Have you done a link and sync
Are the carbs opening all the way at WOT
Is the timer base linkage moving smoothly.

 

[Tommyaleks]

Okay. I appreciate all the help from you guy`s. it`s not easy to know when one saying that and one saying that, all I can do is work trough all the suggestion I gett. flyingscott: I`m about to put this back together now, after that I will follow your guy`s advise. I have had a look at the link/sync and it looking good but I will take another look at that. Yes the carbs is opening at wot. About the timer, I will have a picture up later to day, there is something I quite don`t get to be right. it`s better for you to see first.

 

[Tommyaleks]

Okay guy`s. Back to zero again. The engine is still acting stupid on high rpm`s, good on idle, the carbs are still spiting a little. I have tested the cylinders (drop test) and it fires on both cylinders. The sync on the carbs are good. they open on WOT on the same time and equal. About the timing, I can`t figure this out. The arrows on the pic 2 does not line up with the roller, you can see that the timer linkage is all the way back and it won`t start in this position and the engine will also stop at that position when it`s running. At the same time you have the line on pic 3. To get it to start I have to move it forward, like you see in pic 1. I have tried to adjust the stop screw and the timer linkage so that the arrows will line up with the roller and same time keep the line on the cam with the roller at the carbs. But this is not a easy task. The engine still acting the same. The water bucket is almost black and have oil in it. I have tried to adjust the mixing screws again and the engine changes in rpm but still acting the same. I wonder how fine this fine line is on the mixing screws.

pic 1


pic 2


pic 3

 

[elfelt]

mixing screws? I am having the same prob with a 87 55hp...my carbs have fixed jets, I gave them a good clean and it seemed to really help! where are the "mixing screws" ?

 

[Tommyaleks]

on mine they are on the same side as the last picture show. right behind the linkage there. Not all carbs have those.

 

[flyingscott]

So have you had this motor on a boat in the water yet? Because revving the motor on muffs is a useless test even if it's in a bucket. The carbs spitting is very normal. Get it on a boat and on the lake.

 

[Tommyaleks]

No my boat is on land (repairs) I can`t get it on water until later this year. What I can`t understand is, several engine marinas uses test tanks, even a large barrel, I use a barrel, sorry about that bucket thing, my English is not so good. I had a evinrude 1985 50 hp that had full rpm from bottom to the top, and that one was also in the same barrel I use now. Something is wrong, ether elecrical or fuel system. it`s lot`s of fuel oil in the water too, it smokes bad on higher rpm`s, the water is almost black. if you see the carb picture, is that normal? a pond of milky fuel, almost is there was water in it. Strange thing this is.

 

[flyingscott]

You can only run it in a tank if you have a test wheel.

 

[Tommyaleks]

Okay, I don`t have that and I don`t have any boat on the water yet, so there is nothing to do then? no way to get it to go normal again?

 

[flyingscott]

Okay, I don`t have that and I don`t have any boat on the water yet, so there is nothing to do then? no way to get it to go normal again?

How you are running it is not normal. The motor is designed to run with the prop under water because the water causes exhaust back pressure which it needs. When you rev it on the muffs you get a lean condition which is bad and could damage the motor and the motor never gets to operating temps. You may also have a rev limiter on that motor. There are a few reasons to use muffs diagnosing high rpm problems is not one of them

 

[Tommyaleks]

Okay, now I understand a little better, goes that for a big barrel too?

 

[Tommyaleks]

How can I find out/see if my engine have S.L.O.W function ?