'91 Black Max 150 starting issues

Here's a rundown of what I'm experiencing...

I recently rebuilt the fuel pump and replaced any sketchy lines going to the pump. I also changed the plugs about 2 months ago.

Cold start:

I thought that this would have resolved my issue...but, it still takes a fair amount of cranking to get the engine to fire, and when it does, I have to crank it over a few more times to get it running. After i feed it some throttle it is good. Runs strong at all RPM levels, and will sit and pur at idle. Can not say when the last time the fuel line form the tank to the bulb and bulb to the fuel pump was changed, but i do know that it does not remain firm (from reading the other posts, i should probably change that).

Warm start:

After setting for a while, It will fire a couple of times before running. Often times it will smoke for a bit before calming down and idling.

Thanks in advance.

"91 Black Max 150hp v6

Re: '91 Black Max 150 starting issues

Is the fuel enrichener working? It should dump raw fuel into the mid and bottom carbs for cold start. Are you advancing the throttle for cold starts? That motor should start is less than 20 seconds from dead cold.

Re: '91 Black Max 150 starting issues

Chris1956 said:

Is the fuel enrichener working? It should dump raw fuel into the mid and bottom carbs for cold start. Are you advancing the throttle for cold starts? That motor should start is less than 20 seconds from dead cold.

Click to expand...

I believe that the enricher is working, as I can hear a click when the key is depressed, however; I have not had time to physically check for fuel being dumped to the carbs.

I do, at times, advance the throttle when starting as it seems to help some of the time.

One other thing I have noticed is that the bulb will remain hard if the fuel line is disconnected from the motor. It does not remain hard though when the fuel line is connected. Is that correct?

Thanks for the reply!

Re: '91 Black Max 150 starting issues

those motors have no choke as you know,the enrichener is only needed rarely,try just pumping up the ball,and advancing the throttle a little,and no enrichener when cold,it should fire right up,if the fuel pump is strong,my xr4 and my brigeports are all finicky ,and all have their little quirks when cold,,your warm start issue is typical merc 2,2.4 and 2.5 liter v6,nuthin' to worry about there,

Re: '91 Black Max 150 starting issues

philpete said:

I believe that the enricher is working, as I can hear a click when the key is depressed, however; I have not had time to physically check for fuel being dumped to the carbs.

I do, at times, advance the throttle when starting as it seems to help some of the time.

One other thing I have noticed is that the bulb will remain hard if the fuel line is disconnected from the motor. It does not remain hard though when the fuel line is connected. Is that correct?

Thanks for the reply!

Click to expand...

The motor is pulling fuel through the primer bulb. It should not stay hard when the engine is running. It should not collapse completely, but it will be soft.

To get to the bottom of your problem, you need to do a thorough checkup of your engine.]
Compression.
Bleed line condition, routing, and check valves.
Spark gap test
Carb adjustment, cleanliness, and gasket condition.
Enricher circuit operation.
Starter cranking speed.
Vacuum leaks near carbs and reed plate.

Normal start up procedure for my cold engine. I prime it before I dump it off the trailer.
1. Level the motor, which on the bass boat is near the top of the trim part of the trim and tilt gauge.
2. Advance throttle lever about half way
3. Turn on ignition and hold enricher for 5 - 10 seconds (depending on air temp)
4. While holding enricher, crank the engine.

Normally it roars into life within 3 seconds. If cold it may need to be nursed by bumping the enricher for a few seconds till it warms up.