I need help with a 9.9 evinrude

[Stream_fisherKY]

I have spent hours reading on iboats.com in search of an answer to a problem that <br />I am having with an Evinrude 9.9. So far i haven't found any sure answers so i need some help. I think the engine is a 76 model (either 76 or 74). I just bought the engine last year and since then i have had the carb rebuilt and changed both points and<br />condensors. I was told that the engine had been sitting for nearly three years when i purchased it. Last season i ran the boat several times and i had a recurring problem. The boat will start and run great, that is as long as the plugs can stay good in it. I commonly kill at least 4-5 plugs a day<br />in my little 2 cyl engine. I have tried to pattern it lately and i have noticed that it most often occurs in the lower cylinder. I will be running the engine full power and then you can feel, and hear, it starting to have problems. It will start missing and gradually lose power until it finally<br />begins running on only one cylinder. I know this to be a fact because i have stopped the engine and pulled the plug wires one at a time to see which one is good. It will start and run with just the top plug connected when<br />this problem occurs. I can replace the lower plug and presto! i have a fully functioning engine for a limited amount of time. From the posts i have read so far i have seen what appears to me to be a multitude of possibilities, but given my limited experience with engines i am not certain of anything. My first inclination is to assume a problem with the coil but<br />my problem with this is that i believe the coil would have been completely shot by now instead of continuing the same routine. Am I wrong here? Also, i have tried to determine whether or not there is any water getting into the cylinder but i have not been able to locate any yet, although it is a<br />possibility. That's about all i know to tell you. Please consider my problem and give me any advice that you can. If you have any ideas or suggestions please send them my way. Thanks so much.

 

[DJ]

Re: I need help with a 9.9 evinrude

If you are ingesting water into the cylinder the spark plug will lokk very clean, almost new, when you pull it out.<br /><br />Don't discount coil problems. Older Johnsons and Evinrudes had coils that would crack over time. The coils are not that expensive.

 

[norman158]

Re: I need help with a 9.9 evinrude

whats the plug look like? wet? sooty? dry?carbon bridged? is the fuel pump running off the lower cyl?

 

[Stream_fisherKY]

Re: I need help with a 9.9 evinrude

As far as the pump is concerned i don't currently know. i haven't really dealt with the inside of this engine much at all. I will try to find out tommorrow when i get her open. As for the plug it is usually very dark on the tip but I am not real sure what that suggests. Anyone know? Thanks for everything so far.

 

[Stream_fisherKY]

Re: I need help with a 9.9 evinrude

Any tips on how to test a coil to see if it is functioning properly? Also, i had someone mention to me that the problem could either be a coil (or a piece that is suppose to give power to the coil) don't know the name of the part or it's location. Any ideas?

 

[bencat]

Re: I need help with a 9.9 evinrude

The first thing I would do is a compression test of both cylinders. Can't you swap the top coil with the bottom and see if the problem follows the coil to the bottom cylinder? Lots of luck, I have a 1975 15HP that I work on all the time. My problem is that the engine block is worn where the stator plate rotates on it. I have been able to shim with a .005 metel shim and make it run better but it still gives me a fit at low rpms at times.

 

[scupbaron]

Re: I need help with a 9.9 evinrude

....sounds like a head gasket. Is plug getting a build up of brown crud? ...these little engines are prone to this especially if used in salt water ...gaskets rot, head also. Fortunately its usually a cheap fix ...gasket 10 bucks, heads planed at local machine shop, 20 bucks. Did mine a year ago.

 

[G DANE]

Re: I need help with a 9.9 evinrude

As you can solve the problem temporarely by changing the plug, i think it could be the lower ignition coil, piont or capacitor for this cylinder. Suggest you check theese 3 possibilities. You can check with a spark tester, which gives you the possibility of enlarging spark gap to 3/8", 1/2" or so. You can compare boths sparks that way.<br /><br />Also do the compression test.

 

[G DANE]

Re: I need help with a 9.9 evinrude

Just a thought - do you kill plugs in the upper cylinder too ? This could indicate wrong mixture, caused by wrong iddle mixture setting, wrong main jet, lots of slow sailing ( but it is only a 9.9 ) or missing center gasket between carbureator bowl and body, at venturi.

 

[hallucitrippin]

Re: I need help with a 9.9 evinrude

I used to have a 74 9.9hp evinrude. Had the same problems and it was the coil. A crude method I used to make it back to shore aned figure ou what was wrong was to switch the coil wires every 5 minutes or so, I t would come out of it when the plug fired harded, but the other plug would quit shortly.

 

[Stream_fisherKY]

Re: I need help with a 9.9 evinrude

Thanks for the suggestions. I am going to be breaking the ol' engine open soon and i plan to go through the carb. I will certainly check the gaskets when it's opened up. What kinda compression readings should i get under normal conditions. I don't know what's normal, thus wouldn't be able to figure out what would be abnormal. Thanks.

 

[Stream_fisherKY]

Re: I need help with a 9.9 evinrude

When i replace the coil, which looks like what i'll be doing first, should i do them both or can i get by o.k. by just changing the bottom one? Also, i was looking into buying a repair manual so i can learn about my engine and be able to service it. Do anyone have any suggestions on what manual to buy? Which one is best?

 

[alcan]

Re: I need help with a 9.9 evinrude

I would buy a manual 1st. They are all good. If you don't want to shell out the 30 or so bucks, then check one out at the libaray. My guess is there is a hole in your fuel pump diaphram. this would cause the lower cylinder to flood and foul the plug.

 

[hallucitrippin]

Re: I need help with a 9.9 evinrude

if it was me I would change both coils so that you KNOW that both of them are new and you wont expect anymore problems from the. But yes you can probably get by with just changing 1

 

[Spur]

Re: I need help with a 9.9 evinrude

Alcan recommended I go to the library too maybe I will meet ya there, LOL.<br /><br />THis is a great site for help with boat motors. It helped me get one fired up that was sitting around for ten years!

 

[Stream_fisherKY]

Re: I need help with a 9.9 evinrude

Thanks again everyone. I agree that this is a great site. The best i've found so far by a long shot. I probably will be changing both coils as soon as i can get ahold of them, we are currently snowed in where i live. Also, i will check out the fuel pump problem that was suggested. Only question i have is would it be easy to locate the problem if there were one present, or is it something i'd have to know to look for?<br />Any suggestions are appreciatted. Thanks y'all!

 

[Stream_fisherKY]

Re: I need help with a 9.9 evinrude

G Dane:<br /><br />The upper cylinder tends to only die if i run it for extended time with the lower cylinder already gone. I only know this because i have come home a couple times on just the top cylinder, having ran out of backup plugs, and it has stranded me a time or two. I suppose however that it is dying because of the load. Any ideas?

 

[G DANE]

Re: I need help with a 9.9 evinrude

I would recommend you to test in two ways:<br /><br />1. check the spark, by establishing a kind of gap, 1/2 inch from cord to ground and then pull starter rope. Spark should appear at every compression. If not, reduce gap a bit. Compare with other cylinder. If both sparks are alike, i dont think this is your problem. Spark must be stabile at a gap around 3/16 inch, or you have a weak ignition.( bad coil or stator )<br /><br />2. mixture. Go 3/4 of top speed till the first plug starts to fail. Unscrew the plug in the good cylinder. How does it look ? If mixture is OK it is like coffee with cream. If it is black, mixture is too rich for some reason, if it is grey or light grey you are running too lean.<br /><br />Let us know, when you can tell more, we hope to help you, usually the 9.9 evin is a very fine motor, if maintenanced, it lasts for life. " An evinrude can´t be worn out, but can be ruined by lack of manitenance or incorrect use" that´s what my dealer told mee when i bought my first.

 

[Stream_fisherKY]

Re: I need help with a 9.9 evinrude

G Dane<br /><br />I will be testing those asap. I was told that the mixture for the engine was 1 pint to 6 gallons of gas. That is how i've mixed it so far but you are exactly right, that could be the source of my problem. Before changing coils i will check my mixture again and run the engine on a different mix. So far my plugs look very dark when i pull them from the engine. Could that be caused by anything else? just curious? Also, others have suggested a problem with the fuel pump region. You have info on this? Thanks so much for your help.

 

[Stream_fisherKY]

Re: I need help with a 9.9 evinrude

Hey Guys:<br /><br />I went to check the plugs as G Dane suggested and they are both very black. I then proceeded to check my coils for any noticable damage and made a discovery that could be the source of my problem. Several people had mentioned that 70's model evinrudes were bad about cracking coils. I looked down the sides of both of my coils and someone (previous owner) had placed silicon over a crack in each of them. We pulled the silicon off to reveal a moderate crack in the top coil and a more severe crack in the bottom. Is this my problem? or do i still have others like the mix and so on?