Slow idle

"Hello,
I have recently purch

"Hello,
I have recently purchased a boat with a 1994 V135 Black Max Mercury motor on it. The motor was purchased in southern Oklahoma and I am wanting to run the motor in Northern Colorado. In having the motor on the lake it is very hard starting and is idling at about 625 RPM. I am wondering if speeding up the idle to 750 RPM will solve the cold start and idling problem? All I see on the motor is 6 screws that have plastic ends on them and they only turn a short distance. How do I increase the fast idle?
Thank you very much for your help,

David [email protected]"

" joe
I have a 1995 Evinrude

" joe
I have a 1995 Evinrude 150v6 It has developed an annoying problem. It will sometime shut down just like you turned off the key. The motor will crank but will nor fire, after tilting up and down and turning the wheel and then trying several time it will suddenly fire up and everything is ok. until it happen again could be several month's until it happen again. I don't get a chance to really check it before it's working again. Have you ever come across a problem like this before? Could be the ignition switch? or possibly the power pack. So far it seems to fix itself. "

"Bcliff..... I have seen a few

"Bcliff..... I have seen a few ignition switches that would have an intermitent short within them. It's possible that yours is acting up. If when that happens again, and if you can get at the back of the ignition switch easily, remove the Black/Yellow wire from it. That is the kill circuit leading to the powerpack(s). If the engine now performs properly, I'd suggest replacing that switch. Intermitent problems can really be a pain..... wish you luck.

Joe "

"Dave,

The engine should id

"Dave,

The engine should idle with the throttle plates closed. The idle speed is adjusted by the stop screw on the timing advance lever on the port side of the powerhead.

The idle speed can also be affected by the idle mixture screws (two on each carb). You can lightly seat these screws and then back them out 1 1/2 turns. You might find that the idle speed increases a bit if you close each screw 1/8 turn. You might be able to go another 1/8 turn. You have to use your judgment here.

Set the mixture screws first, then adjust the speed using the stop screw on the advance lever.

If you still can't get it to idle, it probably needs more that an adjustment.

Does the engine seem to have full power when riding at speed?

"

" Tony,
Yes the outboard runs

" Tony,
Yes the outboard runs perfectly at half speed and at full speed of about 62 MPH.
It is just very hard starting and barely runs at an idle.
Thank you,
David "

" It could be the altitude the

" It could be the altitude there in Colorado. I'm not an expert like Tony and Joe, but I have read in my owner's manual that operating well above sea level does/can affect an outboard's performance at idle. Could also be gunked up carbs. Hope you solve your problem. "

"Dave,

Altitude can definit

"Dave,

Altitude can definitely have an affect on performance. You should be able to solve this by adjusting the carbs.

Hard starting can be caused by a choke that is not working properly. On this engine you have an enrichener valve which allows extra fuel for starting. It is electrically operated when you apply choke. If the valve is not opening or not closing, you will have trouble starting and idling.

The valve allows fuel from the float chamber of the top carb to trickle into the bore of the lower carbs. Remove the hose from the valve to the middle carb and see if you notice fuel flowing when you apply choke. Note if it stops when you remove choke.

There are also two brass orifices on the front of each carb. Using different size jets here might help with the altitude problem. I will try to find any recommendations from Mercury about this and get back to you.

"

"Dave,

If you think that th

"Dave,

If you think that the problem may be caused by altitude, here is something you might try.

On the front of each carb, just above the main bores you will see two brass orifices. The one on the left is the idle air orifice, and the one on the right is the vent for the float bowl. These are available in a number of sizes.

I would suggest that you try a larger jet size for the idle air orifice, and see what happens.

"

" Tony,

I adjusted the six

" Tony,

I adjusted the six air mixture screws on the carburators (turned them in about 1/4 turn each and the motor starts right up and idles about 750 RPM. I think that this is going to fix the problem. I will get it on the water hopefully in the next 2 weeks (Blizzard out right now for the Next three days they say). It looks to me like the air mixture just needed adjusted. Probably the thinner air? What do you think? Motor starts at the turn of the key and stays running once its warm.
Thank you very much for your help it has been greatly appreciated. Nearest boat mechanic is around 150 miles for me.

David "