Bad coil? 94' Evinrude 40

christians89

Seaman
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Jan 13, 2011
Messages
55
Intermittently the motor will die from a high rpm down to about 1500rpm and will not go any higher. Sometimes it does it from a cold start or while your already running down the lake. I know its not a fuel problem. Ive cleaned the tank, carbs have been entirely gone through, and while the problem is occurring if you squeeze the primer bulb or hit the choke it just makes things worse and the engine usually dies. Ive also tried unplugging the temp sensor while the problem is occurring but there was no change, was thinking s.l.o.w. Ive tried remedying the problem by closing up the plug gap a little and this made the problem go completely away for about a week or two, but now its back and its getting worse. This is whats leading me to believe its the coil. What do yall think? Thanks in advance!:)
 

Daviet

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Re: Bad coil? 94' Evinrude 40

You can use an inductive type timing light, when the problem occours clamp the timing light to eack plug wire and see if you have spark on both cylinders.
 

christians89

Seaman
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Re: Bad coil? 94' Evinrude 40

Ill give that a try. I also forgot to mention that I cleaned the plug wire ends and inspected the wires for cracks or blisters but they are in excellent shape. If it is running on just one cly during the problem, would the cause still be coil? Anyone else has any ideas/opinions?
 

Daviet

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Re: Bad coil? 94' Evinrude 40

Without a model number, not sure which system you have. If you only have one coil and only loose spark on one cylinder, I would be thinking power pack.
 

christians89

Seaman
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Messages
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Re: Bad coil? 94' Evinrude 40

It does have just one coil. Ill have to get the model number for you. Is there a good way to test the power pack?
 

christians89

Seaman
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Messages
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Re: Bad coil? 94' Evinrude 40

Ok the model number is E40TEL and the serial number is g2515230. Hope this helps in anyway.
 

Daviet

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Re: Bad coil? 94' Evinrude 40

Yes there is a way to check the power pack, but it almost takes a factory manual to explain it and give the proper specs. In my experience if you loose spark on one cylinder, with a single coil system, especially under load, it has always been the power pack.
 

christians89

Seaman
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Jan 13, 2011
Messages
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Re: Bad coil? 94' Evinrude 40

I couldnt thank you enough for your help! Tomorrow afternoon Ill throw the timing light on her and see whats going on then report back. Thanks again!
 

christians89

Seaman
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Jan 13, 2011
Messages
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Re: Bad coil? 94' Evinrude 40

Ok, today I tried hooking up my inductive timing light to each plug wire while the problem was occurring. And BOTH cylinders are loosing spark at the same time while the problem is occurring. The problem usually begins at 2400 rpm, according to my timing light, if throttling it up slowly. I also was able to swap out the coil with a known good coil and the problem was still there. So its got to be the power pack right? It is acting just as if someone was cutting the key switch on and off very fast not allowing the engine to rev up.
I had also read somewhere that the slow feature would not allow the engine to rev up above 2500 rpm if it were running hot, so I also tried unplugging the temp sensor but that changed nothing.
 

Faztbullet

Supreme Mariner
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Mar 2, 2008
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15,589
Re: Bad coil? 94' Evinrude 40

If both cylinders are acting up its more likely a stator as pack problems rarely come and go. Disconnect the rectifier an retest as it could be bad causing stator to overheat.
 

christians89

Seaman
Joined
Jan 13, 2011
Messages
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Re: Bad coil? 94' Evinrude 40

Faztbullet, by disconnecting the rectifier wouldn't the engine loose spark and die? Ill give it a try though and see. The problem comes and goes like the wind, very intermittent. Again its both cylinders at the same time loosing spark then getting it again. Just like someone is turning the ignition switch on and off really fast.
 

christians89

Seaman
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Jan 13, 2011
Messages
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Re: Bad coil? 94' Evinrude 40

Just thought about this, last year there was a serious short on the boat. It fried the entire main harness from the controls to the plug in the engine. However all wiring on the engine was not affected since the inline fuse behind the black plastic electrical box had popped protecting everything. The short was fixed and the main harness was replaced so I haven't had any more problems since now. Its possible that could have lead to this problem.
I will also check the charging voltage of the system. Its never given me any problems starting before but since the rectifier was mentioned I assume it should be checked.
 

mrviper3000

Cadet
Joined
Jun 21, 2010
Messages
6
IS there a fuse box on boats???

IS there a fuse box on boats???

I recently picked up a 1989 Sunliner 15, 7 ft boat... I looked under the sterring colum, and didnt see one.... I has a radio installed in it,,,,, But sdidnt dear turn it on..Since,, Looks like someone been playing under neath there.. I had to buy a fuse box from Westy marine and install one on my 71 Glastron and all the noon cheap wiring they sold me. Yipee lol...... I assuming its all in line fusing, from what i saw.. Just figure I ask the grurus of boating. As I am a novice.... Also told my bottom float maybe need adjusting ( they called t balancing) stated the carbs where re built.... It has a 70 hp Tohatsu. I believe its an 1986 maybe 1992,,, M70A2 it starts with,,,, Any help would be appreicated....:D
 
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