Merc 150 in-line 6 dies when shifted into gear

[fish4fun2]

Hay guys got to say thanks first for all the help and information you give to the less knowledgeable beginners like myself.<br />I have a 1975 merc 1500 150hp motor that I had one heck of a time just to get it started but finally got there and now it will idle, the problem is when i put it in forward it dies unless i leave the warm up lever quarter of the way up and put it in full throttle forward and then it engages but it totally bogged down to where it almost dies and that's in full throttle. I have a pretty good manual but they don't talk much about certain problems....also i changed the water pump and after the motor has ran and i shut it off it will be squirting out the hole for another 10-15 seconds..is that okay?<br />Any ideas about the bogging would be most helpful thanks.

 

[Clams Canino]

Re: Merc 150 in-line 6 dies when shifted into gear

You may need to clean the carbs.<br /><br />Then go through the complete timing and sync post I did here. <br /><br />Between them you'll cure it. <br /><br />-W

 

[mellowyellow]

Re: Merc 150 in-line 6 dies when shifted into gear

might be flooding out? squeeze primer bulb and<br />see if fuel is running out front of carbs. a<br />stuck float is usually the cause.<br />take clams advice above and get carb/rbld kits and<br />do the synch. a lean cylinder will fry real<br />quick on that motor.<br />good luck,<br />M.Y.

 

[dka1ser]

Re: Merc 150 in-line 6 dies when shifted into gear

I know the other guys addressed your carburator problems, but regarding your 2nd question - yes, after you shut engine off the water will dribble out the "telltale" hole, as well as the prop, and other water outlets for a few seconds. The engine drains by gravity after you shut it off, it is normal. <br /><br />- Dennis

 

[fish4fun2]

Re: Merc 150 in-line 6 dies when shifted into gear

Thanks for all the information guys I will clean the carbs timing and sync. <br />Mellowyellow man i got to tell you i was really pumping that bulb, sometimes when it was about to die i would lay into the bulb and gas would shoot out of the bottom and middle carbs(not the top though) and doing that would make it run..<br /><br />Jay

 

[mellowyellow]

Re: Merc 150 in-line 6 dies when shifted into gear

Jay,<br />deff. sounds like a fuel delivery problem.<br />if I were you, I would do the following:<br />new primer bulb if old.<br />new o-ring on quick connect<br />rebuild carbs (pretty big job, lots of stuff to<br />pull off to get at carbs)<br />rebuild fuel pumps<br />if any 1 of the 3 carbs is not working right,<br />it can cause a lean cond. and burn up a piston<br />real quick, especially the top carb.<br />have u done a compression test yet?<br />fuel pumps work off internal engine pressure.<br />good luck, love those 150's

 

[fish4fun2]

Re: Merc 150 in-line 6 dies when shifted into gear

Thanks for the information Mellowyellow Before i even tried to start the motor i did a compression test and they all ranged from 130-135, also i installed new plugs, I should take them out, see how they look now and redo the compresstion test just to see things have not changed. I need to find Clams timing & sync posts also and read up on that, he seems to know a lot about these older motors. What really bothers me is I bought the engine from a guy on ebay who said that it was rebuilt with 20 hours on the rebuild also he stated that he would start it at his location, well the starter solenoid was shot The grey wire to the Choke Solenoid was so fragile when i opened the cover it fell apart, The Green wire from the switch box to the Coil had to be replaced. Most of the wires are brittle. The water impeller was shot and parts of it were blocking the water intake holes on the lower unit...tell you what i think there was no way this was rebuilt.<br />Jay

 

[Kenny Bush]

Re: Merc 150 in-line 6 dies when shifted into gear

Your compression is great, and that motor should run. I would kit the carbs, get a manual and resychronize the carbs and timing. Those straight sixes are tough to idle right. I have been most successful adjusting the "Throttle pickup timing" just a little to get it to idle better. Those motors retard the timing at idle to get the RPM's down to 650. Sometimes I have upped it a degree or two (Only on Throttle pkp).