72 Mercury 1150 loss of power

[72gt150]

I just bought a glastron GT150 with a mercury 1150 engine. The boat sat for two years and I just started the engine. It will idle fine and troll when I engage the throttle; However, when the throttel is increased the motor boggs down and will completely stall out. I think it is a 1972 engine. Does anyone have any suggestions?

 

[Chris1956]

Re: 72 Mercury 1150 loss of power

If the carbs are gummed up, that would do it. If the carbs are celan, then misadjusted idle mixture screws would cause it. Best idea is to clean the fuel screens, and if needbe the carbs themselves. That motor should have small round filters under the fuel inlet to each carb.

 

[72gt150]

Re: 72 Mercury 1150 loss of power

Chris, thanks for the advise. I used carb cleaner yesterday and took the boat out - it started just fine and got up to full speed for as long as I ran full throttle (about 4 miles). After having the boat into neutral for a minute or two - I engaged the throttle and the motor only pushed the boat about 2-3 miles per out. I shut down the engine and sprayed more carb cleaner into the carbs - after about five minutes the engine still only moved the boat 2-3 miles per hour. This went on for about five more minutes and then the boat took off at full speed. The motor takes a couple of minutes to get to a plain (longer than expected for a 115 horse engine on a 15' boat. Once the boat gets to a plain - the engine seems to work much better). I'll be cleaning the fuel screen today and see if this helps! Thanks for your help.

 

[Chris1956]

Re: 72 Mercury 1150 loss of power

You might check the fuel pump diagrham. If it has a leak, raw fuel will get into the crankcase and cause the bottom two cylinders to load up.

 

[72gt150]

Re: 72 Mercury 1150 loss of power

I just bought new rebuild kits for all three carbs and a new impeller. These will be replaced tonight. The fuel pump was just rebuilt. Last night I pumped up the primer bulb and noticed the top two carbs were leaking a lot of gas - Is this normal?

 

[OldMercsRule]

Re: 72 Mercury 1150 loss of power

I just bought new rebuild kits for all three carbs and a new impeller. These will be replaced tonight. The fuel pump was just rebuilt. Last night I pumped up the primer bulb and noticed the top two carbs were leaking a lot of gas - Is this normal?

If the engine is upright the carbs should not leak. You likely have stuck floats or gummed up check valves. Be very carefull of using carb cleaner as the motor is lubricated with the oil in the fuel. Good luck JR