Won't hold an Idle

[imported_Jrod]

I have an 8hp Merc and it has the controls on the tiller OK the problem, It starts first pull 99% of the time. In nuetral I can't give it gas because if I turn the tiller it goes in to forward. If I just leave it in nuetral it dies unless choked. I have made sure there is pressure in the ball, changed spark plugs, It runs perfectly fine when in forward and reverse. I'm stumped any info would be greatly appreciated.

 

[Don S]

Re: Won't hold an Idle

Got a year or better yet a SN for your motor? Is it a 2 or 4 stroke?

 

[imported_Jrod]

Re: Won't hold an Idle

2-stroke, I think its 94-95 I'd have to check when I get home.

 

[Don S]

Re: Won't hold an Idle

I think what you will find on that motor is that the choke knob is actually a primer knob and not a choke. It can also be turned clockwise to increase the rpm.

 

[imported_Jrod]

Re: Won't hold an Idle

So what you saying is pulling it out is the choke but turning it CW will raise the idle?

I'll try it out thanks Don

 

[Harker]

Re: Won't hold an Idle

No, what he said was..it's a primer..pulling it out and pushing it in squirts gas into the intake to help start a cold engine. Turning it clockwise adjusts the idle up to keep it running while it warms up..then you turn it counter clockwise after it warms up. If it's dying out after it is warm, you may want to adjust the idle screw up a bit. You don't want a fast idle all the time as it will make shifting hard on the gears. I have a 99 25hp with the tiller handle shift and I pull/push twice..turn full cw..and start..let warm up for a couple minutes then turn the knob counter cw and go. If it starts to stall out when turning counter cw..give a quick pull/push on the knob till it gets to operating temp. Mine is pretty cold blooded.

 

[imported_Jrod]

Re: Won't hold an Idle

OK I got you. Where is the adjust screw I have no clue about outboards but follow direction rather well. How much do I turn once I locate it

 

[Don S]

Re: Won't hold an Idle

Where is the adjust screw I have no clue about outboards

If you are talking about the knob you turn to increase the idle speed, it the primer knob. It does two things. The same knob you are calling a choke.

If you are talking about the idle mixture screw, if it runs ok warm, don't mess with it. You could get it too lean and burn your motor up, so be sure you know what you are doing.

 

[imported_Jrod]

Re: Won't hold an Idle

I'll try the messing with the primer knob first, see if that helps. I wish the guy I got it from explained this crap before me buying it. I had a Nissan before and it didn't have these funky gadgets. Thanks guy, I'll let you know how I make out. Hopefully in the next couple weeks I'll have it out on the water.

 

[Harker]

Re: Won't hold an Idle

Like Don said..don't go turning screws on the carb. If you look beside the carb..on the left while facing the carb, you can see cables and pulleys that operate your shift and throttle..there is an idle screw on that stuff..just turn it enough so that the "warm" motor doesn't die out. You should get a manual for it or at least an owners manual.

 

[imported_Jrod]

Re: Won't hold an Idle

OK finally the weather broke and I had a chance to go out and run the motor, I primed it twice and it started right up, ran the motor around for a bit and it ran fine yet once again it dies at idle. The prime knob was in, started it again, at idle I turn the primer knob clockwise yet the rpms didn't raise, I took the hood off to see how the mechanism works. I notice a metal bar that when I turn the primer knob left and right it moves but while the knob is turned all the way to the right it isn't enough to engage the throttle to give the carb gas. I can do it manually but the primer know isn't giving the motor gas I hope you can understand what I am talking about.

 

[Don S]

Re: Won't hold an Idle

If you are planning on doing your own work on this motor, I highly recommend you get the OEM service manual. All the adjustments you need are detailed (with pictures). Including the carb adjustment. The manual you need is 90-827242R02. Might even check ebay, this manual was used for MANY years.
Here is some info from that manual with the pics.


IDLE WIRE ADJUSTMENT
1. Push primer/fast idle knob completely in and rotate fully counterclockwise.
2. Shift engine to Neutral.
3. Adjust screw to remove all clearance between idle wire and trigger.
4. Check fast idle speed by turning primer knob to full clockwise position. Fast idle speed
should be 1500 - 2000 RPM.

 

[imported_Jrod]

Re: Won't hold an Idle

Thats awesome don, great info. I'm going to look for the manual. This thing is starting to get on my nerves and
I will end up taking it somewhere but if its something easy I’d rather not.

When I turn the primerknob the bowed lever moves back and forth but turned all the way right the Idle wire
is not even pulling the throttle. Now if I adjust the
screw will that pull the wire closer to the throttle?

 

[Don S]

Re: Won't hold an Idle

The throttle shouldn't move for fast idle. The only thing that should move is the trigger (under the flywheel that the trigger wire hooks too).
What you need to do is a complete "sync & link" as it commonly know as. This sets the WOT timing, then the idle timing and idle speed (throttle). That trigger wire was probably adjusted too tight to begin with or the timing is off or who knows what could be wrong.
But backing off the adjustment for the trigger wire then following the directions in the service manual to adjust everything in the proper order will get it all so it works. But without a manual you don't stand a chance.

 

[imported_Jrod]

Re: Won't hold an Idle

Well Don just wanted to say thanks again I printed out your diagram and took it home, the idle wire was flipped the other way resulting in no contact with the throttle, now the bar is in contact with the throttle but just a little bit. I think it may have done the trick I'll find out this weekend. I think the guy I bought it from was messing around with something. I'll let you know how I make out.

 

[imported_Jrod]

Re: Won't hold an Idle........now white fluid

Re: Won't hold an Idle........now white fluid

Took it out again over the weekend and it still doing the same thing I am taking it to the shop, but I also noticed a white fluid coming from the exhaust and idea of what that could be. I'd rather not drop it off with no clue of whats going on.

 

[Harker]

Re: Won't hold an Idle

The white stuff is unburned exaust..more than likely. The previous owner may have dis assembled the carb for some reason and didn't get the stuff back together correctly. There is a lot of stuff on those carbs and I had to really pay attention when rebuilding mine to get all the things in the right place.