1987 Mercury Classic 50 (45 hp) 4cyl SN OB258460
A few weeks ago while drift fishing - after 20-30 minute drifts we would have to pump the primer bulb to get the engine to start again which was not normal. I tried changing from the internal (belly) gas tank to my 5 gal spare, but same problem. Generally the engine ran fine once stared, but did bog and almost stall at one point while running.
I started the engine at home 3 or 4 times over the next couple weeks. At first the motor would run at higher RPMs, but stall when RPMs got down near idle. The problem kept getting worse until the last time I ran it I could not pump up preassure in the primer bulb, and the engine would not run, or barely run at all.
Note - the symptoms are the same regardless of which gas tank I am hooked up to (belly tank or 5gal spare using different supply hoses). I checked the section of supply hose inside the engine cowling and all seems fine.
I rebuilt the gas pump. Now I can pump preassure into the primer bulb again, and the engine will run at higher RPMs, but still stalls at idle. While reducing engine speed as it gets down to about 1500 rpm, it seems to run out of fuel and the stalls.
I have been told that similar symptoms can be caused by leaking top engine seal because not enough preassure is getting transmitted from the crank case to the fuel pump. Anyone else heard of this, know it to be a problem?
What is the appropriate idle rpms for these engines, is 1500 too slow indicating a carb adjustment? (I have only owned this engine a few months, and now have the factory service manual on order).
Any advice or ideas would be apprieciated. Thanks.
Tim
A few weeks ago while drift fishing - after 20-30 minute drifts we would have to pump the primer bulb to get the engine to start again which was not normal. I tried changing from the internal (belly) gas tank to my 5 gal spare, but same problem. Generally the engine ran fine once stared, but did bog and almost stall at one point while running.
I started the engine at home 3 or 4 times over the next couple weeks. At first the motor would run at higher RPMs, but stall when RPMs got down near idle. The problem kept getting worse until the last time I ran it I could not pump up preassure in the primer bulb, and the engine would not run, or barely run at all.
Note - the symptoms are the same regardless of which gas tank I am hooked up to (belly tank or 5gal spare using different supply hoses). I checked the section of supply hose inside the engine cowling and all seems fine.
I rebuilt the gas pump. Now I can pump preassure into the primer bulb again, and the engine will run at higher RPMs, but still stalls at idle. While reducing engine speed as it gets down to about 1500 rpm, it seems to run out of fuel and the stalls.
I have been told that similar symptoms can be caused by leaking top engine seal because not enough preassure is getting transmitted from the crank case to the fuel pump. Anyone else heard of this, know it to be a problem?
What is the appropriate idle rpms for these engines, is 1500 too slow indicating a carb adjustment? (I have only owned this engine a few months, and now have the factory service manual on order).
Any advice or ideas would be apprieciated. Thanks.
Tim