150 Black Max dies after 30min

[dboner]

I have an 1983 150hp Blackmax ser.# 6222134, the problem is that after 30min @ 3500rpm the motor starts to die. I press the fuel bulb and it starts running. I have changed all the fuel lines, installed new switch boxes, Installed new fuel pump kit, check the tank ventilation. I ran it with a 6 gallons portable tank but it did the same thing it flat out the bulb, after press and suppply fuel to the motor it starts to work. What else I can do ? I is turning me crazy!!!!, Thanks for any help

 

[KCLOST]

Re: 150 Black Max dies after 30min

Carb rebuild yet? Fuel Filter?

 

[dboner]

Re: 150 Black Max dies after 30min

Yes, new racor and the carbs are rebuilt

 

[LubeDude]

Re: 150 Black Max dies after 30min

Have you replaced the bulb? The valve may be sticking. Sometimes its the simple things.

 

[dboner]

Re: 150 Black Max dies after 30min

Yes, I replaced the prime bulb. But still doing it.

 

[KCLOST]

Re: 150 Black Max dies after 30min

Ok, Based on your symptoms, the engine just flat isn't getting full after a bit of running...<br /><br />I have to say, that you have the classic signs of a non-venting tank... Are you sure that the Vent is open? <br />Second, are you sure that you're fuel line is the correct size?<br />Third, is there an inline fuel filter on the fuel line (before the primer bulb) that could cause a restriction?<br />Forth, is there a fuel filter inside the tanks?<br />Fifth, did you replace the male a female fitting on the fuel line that connects to the tank and engine?<br />Sixth, Is there any kink in the fuel line anywhere...<br />Seventh, Are you sure that the carbs are set properly...With the engine off, prime the bulb until firm and keep squezzing it and look at the carbs to see if any fuel is leaking from the carbs anywhere...<br /><br />Let us know... I hope you don't think these are stupid questions, but we want to try to cover all the simple stuff first...

 

[KCLOST]

Re: 150 Black Max dies after 30min

By the way, are you sure you are not overheating the engine? Is the alarm working properly...

 

[dboner]

Re: 150 Black Max dies after 30min

Thanks, I will try all this. The tank is a below deck 110 gallons aluminium and I will do all the ckecks you just told me. Thanks for the help KCLOST

 

[dboner]

Re: 150 Black Max dies after 30min

The engine is running between 140 and 170 and the water pressure is high all the time.

 

[dboner]

Re: 150 Black Max dies after 30min

There is a sensonr in the motor that if ti goes over 180 shuts down the motor?

 

[quantumleap]

Re: 150 Black Max dies after 30min

Check the vent line coming from the tank for obstructions. Or open the gas cap after 15 or 20 minutes and see if there is abnormal vaccum. Is the tank full or partly empty now?

 

[dboner]

Re: 150 Black Max dies after 30min

he tank it is 1/4 now

 

[LubeDude]

Re: 150 Black Max dies after 30min

KClost and Quantumleap are addressing the issues I would think to be the problem as well. You say that the engine is sucking the primer bulb flat???? The only way that could happen is if the vent isnt open, or there is a restriction in the inlet of the fuel pick-up tube. Im assuming that there was a different fuel line with the portable tank. Because it happened with the portable tank also, did you remember to open the vent on the portable tank?

 

[dboner]

Re: 150 Black Max dies after 30min

It was a different kind of fuel line on the portable tank. I full opened the vent of the tank and ran it for a while. I think I need a mercury specs prime bulb for the fuel line.