1995 Merc OB stalling at low speed

[telemorgan]

I just bought a 1995 Sea Pro that has been sitting on dry dock for 2.5 yrs. I was properly maintained and very clean. After purchasing, I replaced water seperator, primer bulb & inline fuel filter, pumped out all old gas and replaced with 93 octane. When I took it for a ride the first time it would stall at very low rpms (low speed). When I would pin the throttle all the way it was fine. Also going at a moderate rate of speed the engine would sound like it was struggling (3000 RPM to 4000 RPM then back to 3000 RPM), any ideas on where to start to troubleshoot this?? All suggestions welcomed. <br /><br />Thanks in advace.

 

[schaiss]

Re: 1995 Merc OB stalling at low speed

Carberators. Pull em off. I bet you will find at least one of the main jets plugged. The main jets are located on the bottom, idle jets located on the top. If you do one carb at a time you should be able to do this work yourself (I did). Carb dip is sold in auto parts stores for about $12 a gallon. Dip METAL parts only, this stuff eats anything that is NOT metal. If the engine was stored with a liitle bit of fuel in there, it will turn into jelly over time and plug up the jets (particullarly the main jets on the bottoms).

 

[gss036]

Re: 1995 Merc OB stalling at low speed

Try using SeaFoam 1st, it might do the job for you, lot easier than carb cleaning. Mix it very strong w/gas in a small container.

 

[telemorgan]

Re: 1995 Merc OB stalling at low speed

Thanks guys, we took the carbs off this morning and they were pretty clogged. Will give them a good cleaning and let you guys know what happens. Thanks for the help on this issue. <br /><br />One other question I would like to ask you guys. As I stated before after purchasing the boat I replaced the inline fuel filter. Before starting the engine, I prime it with the primer bulb and see gas begin to fill up the filter. When the engine starts however and it is idling or in gear the gas level gets lower and lower in the inline filter to the point where it just looks like it is just "spitting" gas in there. You no longer see a solid line of gas half way or quater of the way filling the filter, the gas is just spitting (for lack of a better word) around in there. Is this normal? As I will need to purchase a carb kit to get the carbs back online, I am thinking about getting a new fuel pump diaphragm as well for it might be a little stretched out and worn. What do you think?

 

[schaiss]

Re: 1995 Merc OB stalling at low speed

Check the easy thing first. Make sure there is no restriction in the vent line running from your fuel tank a fitting on the hull. If this is plugged it will cause this condition. If the vent is clear, check valve at the primer bulb or the in the line where the oil feed tees in (gas would be backfeeding into the oil tank). Last, check the fuel pump. Provided the drive on the pump is OK, a rebuild kit for a fuel pump is pretty cheap and easy to install!<br /><br />Good Luck.<br /><br />I am sure you will LOVE the throttle response on your engine with those carbs cleaned. REMEMBER: Do not over rev (above 3000 rpm) your engine on the muffs. Stock intake reeds are metallic and are suseptible to stress failure. YUCK!