9.8hp won`t idle?

[Rotti]

Hi,
normally I didn´t want to bother you with this question that possibly might have been asked some hundred times before- but I simply don`t know how to use this FUCKIN search engine! :|

I`ve tried now for some 30 minutes just to end up with either no matches at all or 50 pages full of matches that don´t answer my question!
Where can I get an explanation of what I have to type in for a search that would turn out some matching threads? My problem is as simple as this:

Mercury 9.8hp won`t idle!

So what do I have to fill in to search this forum? I`m not a computer-hack, no way, but it seems to me that one has to be before he can start fixing his outboard!

Sorry for these harsh words but my blood pressure is already in the red- the search engine they`ve installed in here is just another example of stupid over-engineering! And if they still want to keep it, they should at least give some explanations of how to use it!

 

[Rotti]

Re: 9.8hp won`t idle?

Ok, forget that search-stuff, it`s just hopeless. Fooled with it for another 20 minutes and the results just get worse.......

Here`s my problem:
My outboard is a 1987 Mercury 9.8hp. Very nice condition but hasn´t been used for decades! So first thing I did was taking apart the carb and put all the parts into the ultrasonic cleaner. Everything came out nice and clean, all jets seem to be free. When I had everything back together I put the motor in the tank and tried to start it. After pulling the rope a couple of times it came to life, choke was pulled. It reved very high so I closed the throttle and tried to push in the choke- died immediatly.
I can only keep it running with the choke pulled, so that the flap at the intake is 80% closed.
This tells me that with the choke completly open the engine doesn`t get enough gas, right? When it has died that way, I just have to pull the choke out again (flap closed), pull the rope just one time and it fires a couple of times before it dies again. After pushing the choke back in I can start the engine and keep it alive for some seconds, but it revs way too high, so maybe the mixture is already too lean as well?

I just want to hear some experts opinion on this before I take it apart again- my guess is that maybe the float is misadjusted, so that there`s not enough fuel in the bowl (engine needs more vacuum to drag some fuel up through the jets)? Or what about this funny gas pump which sits directly attached to the carb (it´s a Mercury carb, not a Tillotson)? Could it cause a behaviour like this?

Any help would be great since I don´t think that there`s something actually broken, looks and behaves more like it`s just not tuned correctly......:/

regards,
Wolfgang

 

[Laddies]

Re: 9.8hp won`t idle?

If the low speed needle is set at about 1 1/2 turns then, there is a low speed pick up tube that supplies fuel to the low speed idle screw, it is under the brass sloted plug on top of the casting the idle mixture screw is in it is either plugged or there is a vacume leak at the brass plug or the soft plug on the side of the carb

 

[Rotti]

Re: 9.8hp won`t idle?

Hello Laddies-

I´ve had that tube out yesterday, it was dirty somehow but not really clogged. In my manual they said that the idle mixture screw should be set to 1 turn out- however, I´ve tried several settings with no results.
Where exactly is that soft plug you`ve mentioned? Couldn`t find anything like that?
When I had the carb apart and put it in the ultrasonic, I didn`t take out that idle tube because I couldn`t unscrew the brass plug with the carb in my hands. The whole carb was very dirty from the oil that was left over when the fuel itself evaporated over the years- that was really like a very sticky grease!
Could there be some channels still clogged which have to do with the idle setting of the engine? I only have one of those universal manuals which cover all kinds of motors and that`s why I can`t exactly see how the fuel or air is supposed to travel through the carb...... :%

Greetings,
Wolfgang

 

[Laddies]

Re: 9.8hp won`t idle?

Wolfgang, the soft plug I talking about should be on the port side of the carb, they used a couple of differant carbs can you give the number stamped on the carb to help identify it -- Bob

 

[Rotti]

Re: 9.8hp won`t idle?

Hi Bob,

I´ll look that up later and will also take some pictures- post the URL so you can take a look by yourself, ok?

CU

 

[rainycity1]

Re: 9.8hp won`t idle?

When my 9.8 would not idle I tried all the carb and fuel stuff and then discovered that I had a dead ignition coil and it is very common. There is one for each cylinder. You can test the coil with an ohm meter between the end of the plug wire and the bare wire on back of the coil. If you get no continuity, it's dead. You have to remove the coils to test. Check both to verify. Your problem may well be different but it's something to look at.