'89 150 BlackMax idle/start problem...
 

I'm hoping someone can shed some light on the idle/start problem I'm having. The symptoms are:

1. Difficult to start. However, I can always get it started by increasing the throttle.

2. Once started it will rarely idle. After around 10 minutes of keeping the rpms up with the
throttle it idles fine.

Some things I've done so far:

1. Cleaned the carbs

2. Rebuilt the fuel pump

3. Changed fuel filters (external and the one on the motor)

Questions I have are:

1. Anyone know what years that the '89 150 BlackMax carbs are interchangeable with?

2. Anyone know how to test the idle stablilizer module?

3. Where's a good source to get a manual? I hear that the Seloc is not a good one.

Thanks,

Rey

Throw the idle stabilier module in the garbage (along with the oil injection) and have a good mechanic set the timing on that motor. A good sync and link should help. Bad reeds can also cause starting/idle problems. Check compression of the motor too while your at it, just to be sure. You can find Mercury factory service manuals on ebay for cheap.

Good luck!!

Thanks Big. I did read somewhere about just removing the idle stabilizer module. I believe I found it located on the throttle linkage side of the engine near the rear of the engine. It had 3 wires plugged into it in addition to a bunch of wires in a harness coming out of it. I disconnected the 3 and there was no affect on the idle. What would a bad reed valve look like? I don't recall the compression numbers but I do know there were all within a few lbs of each other. I'll check out eBay on the manual...thanks again!

2 things i would have a mechanic check but i hope you can find an honest one, good luck on that
1st the carbs might have to be rebuilt
2nd the stator
good luck
if you live in nj go to anglers marine in seabright nj there the best and honest plus they will fix your boat right the first time

I've rebuilt the carbs but for it to idle after 10 minutes of warming up leads me to believe something else is going on. Something else is being affected by the heat.

I'm not sure if the carb is good in the first place. Jets have been replaces and from what I read the jets of all 3 carbs might be matched, so that's why I was wondering if I can use other year carbs on this '89.

what rpm are you trying to idle at?

From what I've read, the idle should be around 750 +-. If it idles high, then I might not be able to get it in gear; so I've read.

750 to 1000 should be good
those motors have alot of electrical switches and boxes it could be electrical problems
i have a 1988 and i had to change my stator 3 times and the simptoms vary

what kind of tach are you using to set the idle rpm, the one in your dash is probably not accurate enough at low rpm, I set the idle rpm usually by ear if i don't have my shop tach handy. I set it high enough where it will idle in gear, but when I pull it out of gear and back in, the boat doesn't lurch and you don't have a big clunk when shifting, try going from fwd to reverse, as long as it stays idling, adn it doesn't shift too harsh, you should be ok

Is it easy to test the stator? If so, can you give the steps on how to do it?