How do I put new jets in carb.

[sstoc]

Hello over the weekend I went up to the mountains (8000 feet) and the boat ran good but no power. I tried everything hotter plugs, octane booster, air fuel mixture, new lower gear oil. I even checked the compression 135 all 6 cylinders. Coming home we stopped by another lake at 4000 feet altitude and the boat ran great. In 2 weeks Im going back up to the mountains so I thought I should try changing the jets in the carb. I have a 1977 tower of power mercury 1150. I dont know where the jets are located in this engine. Can I change the jets without removing the carbs? And does anyone have a engine breakdown for this motor? And does anyone know where to buy jets for this year of motor? And what size jets I need for 4000 to 8000 ft. Thanks Tony

 

[Yepblaze]

Re: How do I put new jets in carb.

I dont know where the jets are located in this engine. Can I change the jets without removing the carbs?

There are a number of jets in a carb. In different locations within the carbs.
They (the main jets) are probably in the back of the float bowls. You may be able access through the bowl drains.

And does anyone have a engine breakdown for this motor?

They are quite prevelant online such as this http://www.dougrussell.com/partscatalog/index.cfm

And does anyone know where to buy jets for this year of motor?

Order them from a dealer

And what size jets I need for 4000 to 8000 ft. Thanks Tony

Maybe one or two sizes smaller.

BUT BE FOREWARNED

If you run lean it will destroy the motor.

If it turns out well and you happen to run it at lower elevation with these new settings, you might expect to see one of the pistons (or portions there of) come out the exhaust as smoke as the piston melts away.


Personally, if you need to ask these questions, It's my belief that it's probably a job you should not try.

 

[Chris1956]

Re: How do I put new jets in carb.

High speed jets are under the brass hex plug on the bowl. Idle jets are under brass plug (straight screwdriver slot) on the top of the carb, where bowl meets barrel.

Your Merc Dealer will have the jets (hopefully) and will have an elevation chart for that motor. This info is also in the OEM Service manual.