1989 20 hp Mercury Outboard not accelerating, initially

[vichox]

I've had my 1989 20 hp mercury for 5 years and it works great. Yesterday, I started the engine like normal (squeezed the priming bulb, pulled the choke out a couple of times) and let it sit on idle for about 2 minutes. When I tried to accelerate, the engine would start to die. I left the engine on idle and used my trolling motor for a while, but when I tried to accelerate it would start to die again. While this was happening, I pulled the choke in and out while accelerating and was able to keep it running, until it was finally able to accelerate and resume normal function. After it was off for a while (while I was fishing), the engine would start and operate normally.
Yesterday, I changed the spark plugs, looked at the fuel filter and everything seems normal. Any advice on what else I should do? I have the repair manual and want to keep expenses down, if possible.

 

[roscoe]

clean the carb.

 

[vichox]

So yesterday I bought the carburetor repair kit for my engine, took the carburetor completely apart and put it back together, and I'm still having the same problem!
I replaced the fuel line, the gas tank, spark plugs. The engine starts fine after priming, but unless I keep squeezing the priming ball, the engine will stall. I can run at full speed while priming the ball. The problem seems to be not generating suction. I checked all the connections between the fuel filter and the carburator and the gas line and all the connections and there are no leaks that I can spot. Please help!

 

[Bondo]

So yesterday I bought the carburetor repair kit for my engine, took the carburetor completely apart and put it back together, and I'm still having the same problem!
I replaced the fuel line, the gas tank, spark plugs. The engine starts fine after priming, but unless I keep squeezing the priming ball, the engine will stall. I can run at full speed while priming the ball. The problem seems to be not generating suction. I checked all the connections between the fuel filter and the carburator and the gas line and all the connections and there are no leaks that I can spot. Please help!

Ayuh,..... Sounds like the fuel pump is dyin', or fulla crud,....

 

[racerone]

Possibly the low speed mixture is too lean.----That results in a very smooth idle but there will not be enuff fuel to accelerate the engine.---Open it up 1/8th turn at a time and see what happens.

 

[vichox]

Ayuh,..... Sounds like the fuel pump is dyin', or fulla crud,....

Bondo- I replaced the fuel pump gaskets and diaphragm already and still not working. The engine will eventually run out of gas even on idle, but faster when accelerating. My fuel pump looks like the one on page 22 here http://1manual.com/Mercury%20manuals...26883r2/3a.pdf
My serial number is 0c207655.

 

[vichox]

I just checked the compression and both cylinders read about 105 psi. I also got a test gage to test the suction coming from the fuel pump, which I'll test tonight. Anything else I should look into?

 

[quicktach]

Set the carb float to spec? Tried any Seafoam?

 

[Mi duckdown]

Did you rebuild the enricher/choke?

 

[vichox]

While I was taking the carburetor appart for the third time today, i finally found the problem!! the gasket that came with the service kit to connect the carburetor to the engine did not have a hole for what I'm assuming to be the source of suction for the fuel pump. I replaced the gasket, tested the vacum on the fuel pump inlet and the engine is back to normal. I took out the boat to the Willamette and my gps speed gage showed that I'm going faster than before and now my outboard starts after one pull. Thanks for everyone's help. After this experience, i feel i understand my engine a little better.