1978 9.9hp evinrude problems

rjr13713

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It was running fine until about the 3rd time I used it. I was running it and all the sudden it would bog down and die. It would run ok with the choke open. I researched and it looked as though the carb needed to be rebuilt. I ended up getting a 1976 15hp carb and rebuilt and installed it. I got a new gas tank and hose with the bulb to help eliminate the carb from getting more gunk in it. When I got it all together I stuck it in my trash can filled with water and it worked like a champ. Fast forward to about 3 days later, about to head out fishing. I tested it really quick to make sure it was all good and it would run for a minute then die. If I squeeze the bulb it will help it keep going and if its dying and I pull the choke out it will rev back up a little for a second or 2 and then die. I've tried adjusting the idle needle every which way and even if it does make a difference in how it idles, the motor will just die anyways. I did a little more research and found an old thread on here with what seems to be the same problem. A few people were saying its a bad fuel pump. I replaced that and it seems to run a little longer than it did before but ends in the same result with the engine dying. I'm stumped as to what I should do next, any help would be much appreciated!
 

mekkamaz

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Re: 1978 9.9hp evinrude problems

Did you check the carb float level? Maybe it is too low and there is no enough fuel. Try also to prime the bulb when you hear its about to quit just to troubleshoot fuel pump. If there?s a improvement maybe the fuel pump is not working propperly, This are vacuum operated, so check if gasket to the block does not break or misplaced.
 

rjr13713

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Re: 1978 9.9hp evinrude problems

I haven't checked the carb float level. How do I adjust that? just bend it upward? The motor does rev back up when I prime the bulb just before it dies out. I just replaced the fuel pump though and it does the same thing.
 

AlTn

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Re: 1978 9.9hp evinrude problems

does the motor restart easily once you've reprimed it with the primer bulb on the fuel line?...trying to determine if you are losing spark or fuel....as to the float adjusting....it should be parallel with the carb body when the carb is inverted
 

rjr13713

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Re: 1978 9.9hp evinrude problems

it does seem to have a hard time starting. After I replaced the fuel pump it seems to start more consistently but still has a hard time unless I prime the bulb.
 

mekkamaz

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Re: 1978 9.9hp evinrude problems

Do you rebuilt the pump kit? Have you double check if has been propperly assembled? Sounds more a fuel problem than a spark one..try to check float, pump, and then re-test. Tell us how it goes...
 

JDusza

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Re: 1978 9.9hp evinrude problems

Stick with the carburetor.

I wouldn't play with the float adjustment (bending) just yet. Bending the float can set you up for another malfunction once everything else is corrected.

There's two paths the gas can take with the carburetor: high speed path, and low speed path.

How does it run at high speed? Can it maintain high speed or does it die at either high or low speed?

Stick the engine in a bucket again and try to manipulate the throttle cam follower by hand to get the revs up and see if it will stay running at mid to high speed. If it does, the problem is with the low speed path.

When you did the carburetor, did you clear the jets? Did you remove the Welch plug and clear / reem the low speed jets beneath?

Sounds like you have crud in the jets.

J
 

Rick.

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Re: 1978 9.9hp evinrude problems

http://epc.brp.com/Index.aspx?lang=E&s1=f1a4b321-54a6-42a7-8efb-6f35eafc71eb
http://www.sschapterpsa.com/ramblings/Ramblings.html

Here are a couple of sites you should have a look at. Both will be of great assistance. If you elevate the tank over head the pump you can pretty much eliminate the fuel delivery as a problem unless you pickup screen is plugged. Having read your posts I would bet you carb. needs more cleaning. It is not uncommon to hear of people cleaning them more than once. Best of luck. Rick.
 

rjr13713

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Re: 1978 9.9hp evinrude problems

I soaked the carb for a few days in a carb cleaning solution and blew it out. I did remove both welch plugs and clean those jets. It seems to run alright at high throttle but it will eventually die out. At low throttle it seems to die fairly quickly. I'll try elevating the fuel tank and see if that fixes anything.
 

rjr13713

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Re: 1978 9.9hp evinrude problems

ok, I put the fuel tank up higher than the motor and started her up. Ran like a champ, didnt act like it was gonna die at all. I ran it for about 5 minutes then thought i'd try putting it back down in the boat. Opened the throttle and about a minute later it dies out. Do you guys think there could be enough air sucking into the hoses somewhere to cause it to loose the vacuum and starve it of fuel?
 

Rick.

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Re: 1978 9.9hp evinrude problems

That is very possible. In the link I posted to Leeroys Ramblings there is a pump rebuild article. You may want to look at it and make certain your pump is put together correctly. Rick.
 

dazk14

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Re: 1978 9.9hp evinrude problems

Let's get back to the previous question, what did you do regarding servicing/replacement of the fuel pump? Did you replace the gasket?
 

nwcove

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Re: 1978 9.9hp evinrude problems

have you tried a different tank? ( i had a very similar problem with a motor i bought new and only used it for about 20hrs, the motor was always stored indoors/heated basement, but the tank spent 4 winters in a damp shed) to make a long story short, the pick up tube inside the tank had a rusted through pin hole, and the motor was sucking air and it was running out of fuel.
 

jmendoza

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Re: 1978 9.9hp evinrude problems

This problem comes up all the time, and I'm surprized we keep re-inventing the wheel. The key here was he replaced the carb and it did the same thing, plus he replaced the fuel pump, so it ain't a carb or pump issue.

Here is what is most likely if the carb and pump check out good:

1.The fuel line from the disconnect fitting to the pump has gotten hard and is leaking air. Solution is replace the line and use new clamps on it.

2. The fuel line from the tank to the engine has disconnect fittings on each end, and the orings in the fittings are leaking air. Solution is to remove and replace the o rings, or replace the fittings with new ones, or buy a whole new line with fittings and bulb.

3. Pull the fuel line off the carb and with the tank connected to the engine and pull the engine through; fuel should come out of the line that went to the carb, indicating a good pump.

I know you are leaving the tank vent open, right?
 

mekkamaz

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Re: 1978 9.9hp evinrude problems

I?ll stick looking for a pump issue. If there were a vacuum leaking, it will run fine a couple of min. (only the time to empty the carb bowl, fuel line) and die...but between the pump and the carb if the first one is not delivering enough fuel, pretty much to me that not enough fuel is getting on the bowl... that maybe the problem. Check the float first.......
 

Rick.

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Re: 1978 9.9hp evinrude problems

It is frequently difficult to trouble shoot from a distance (or even with the motor at hand for that matter). There are so many things that can be the culprit. I realized he said new pump but sometimes that means a new used pump off an old engine. A rebuilt carb. off another model year/HP could mean a wrong roller cam set up. You know what I mean. My first law of trouble shooting is ' never assume anything' so that is why I suggested it could be the pump (even though I know it was replaced). There are loads of good suggestions above, no doubt about it. Rick.
 

nwcove

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Re: 1978 9.9hp evinrude problems

i like to trouble shoot fuel delivery issues starting at the the tank, and i dont mean the connector, issues inside the tank can cause alot of grief and cost money that doesnt need to be spent. its a simple procedure to put an open ended line, in a tank....or jerry can, pump it up, run it, and see if it changes anything. 9 out of 10 times, a simple problem gets turned into a major unknown issue....thats as simple as an o-ring / hose clamp etc etc.
 

rjr13713

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Re: 1978 9.9hp evinrude problems

Thanks for all the help guys! I was looking over the instructions linked earlier for the fuel pump and pulled the new one apart then put it all back together the correct way. Got it on the motor and it runs like a champ again. I'm taking it out on the river tomorrow so I'll let you guys know how it goes.
 

Rick.

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Re: 1978 9.9hp evinrude problems

Well that's what this forum is all about. Hope we here good things about tomorrows run. Rick.
 

AlTn

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Re: 1978 9.9hp evinrude problems

yep...hope problem is solved...post back
 
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