motor not reaching top rpm Intermitently

[bonessk10]

I have a 1984 90hp inline 6cylinder merc.<br />new carb kits new fuel pump kit<br />the motor starts fine cold but after running for a while or after running at slower trolling speeds the motor will not come back up to full RPM seems to hold up at 1500-2000 RPM.Doen't help to squeeze fuel bulb when this is happening.<br /><br />I noticed when I was running it in the yard that i had a good stream of water coming out of the return line from the motor head. Now below the motor housing on the top of the lower leg there are two ports, that also have exaust gasses coming out of them with a little bit of water however the one didn't appear to have any exhaust gas and absolutely no water coming out of it.<br /><br />Could this be causing the motor to over heat?

 

[Chris1956]

Re: motor not reaching top rpm Intermitently

bonessk10, How do you know the motor is overheating? Your description of the idle relief port operation sounds like it is working OK. If it is overheating, you will need a new impeller installed.<br /><br />I would check to see if your plugs are fouled, after trolling. If the plugs are fouled it is either dirty carbs, misadjusted idle mixture, or possible leaky fuel pump diaghram.

 

[nos1013]

Re: motor not reaching top rpm Intermitently

Or even floats set slightly too high, as I learned the hard way. It does sound like it's running rich. On the muffs, is it smoking so much your neighbors don't have to use the Off?

 

[bonessk10]

Re: motor not reaching top rpm Intermitently

On initial start there is a puff of blue but nothing that I would be concerned about bothering the neighbors. as soon as it fires up it runs clean.<br /><br />I have since put in new plugs and a new starter solenoid as old one disintingrated in my hands as i waschecking wiring<br /><br />The carbs and fuel pump were rebuilt this spring and motor only has about 5 hours on it since that was done.<br /><br />Sorry I didn't respond sooner I missed these posts somehow?<br /><br />My throttle cable end towards motor has about 3/4" on springy play in it is this normal?