OMC 5L won't go over 2500 rpms

[kicks2]

Have ‘88 OMC w/GM 305 – Carter 4b Carb. The engine runs well at idle and up to 2500 rpms with out a load or under load. The problem starts when accelerating, (with or with a load) the engine bogs, spits and will stall. <br /><br />I have installed new points, plugs, condenser, rotor, coil, water/fuel separator filter & Carb fuel filter. The dwell & timing are correctly set and oiled the distributor advance weights. <br /><br />I have check the following for blockage -fuel tank vent, the fuel tank gas line, siphon valve, gas line from the gas tank to the separator and from separator to fuel pump! No blockage!!! After all of this – it still runs the same!? <br /><br />I have also checked the fuel pressure at the entrance to the Carb, it reads 3.5 psi. Should I replace the fuel pump? Have I over looked something? If anyone could help id my problem, it would be appreciated<br /><br />Thanks, Joe

 

[metwrench]

Re: OMC 5L won't go over 2500 rpms

Hi Joe,<br /><br />There was another Posting about an OMC that wouldnt go over 3000, did you read the responses ? Lots of good ideas and he seemed to Fix the problem with them.<br /><br />On your Timing, is the Distributor Advancing ? Check with the Light. At idle watch your timing marks and Note the location, as You accelerate the timing should ADVANCE slowly.<br /><br />Also, as stated in the other Posts, Look at the Metering rods and Float level in the carb. 3.5 Psi from the Pump is Fine ( 4 to 7 is Normal ) But 3.5 will run it fine.<br /><br />If the Tune-up and Dwell is Good, and the timing is ON and advance works, Look toward the carburetor<br /><br />John

 

[liquidasset]

Re: OMC 5L won't go over 2500 rpms

I just fixed this problem in my engine. We checked everything from the timing to fuel pressure too. Rebuilding the carb fixed the problem. Mine was pretty dirty and the float was really far off. It wasnt letting enough fuel into the bowl. The kit is available from autozone for 18$. Hope that helps.