Delayed holeshot and poor idle, but good WOT

Dear Doc,<br /><br />I have a 1997 4 cylinder 115hp 2-stroke Mercury Outboard. Recently stored in backyard for two months and now it's acting up (let me guess, your thinking "heard this one before"). <br /><br />Holeshot response is seriously delayed. If I hammer the throttle down hard the engine responds reluctantly and then picks up and runs like magic in the 3000+ rpm range. If I come to full stop then hit WOT it has delayed holeshot if I let it idle for a little while (if in idle it begins to sputter the holeshot is always delayed).<br /><br />At idle it tends to go into a rough sputter and eventually cut out, at 1000rpm to ~2000 rpm the motor runs rough (engine shakes and kicks). I set the idle speed up a notch to keep it running longer in idle but it doesn't really seem to adjust the idle like it should.<br /><br />Installed fresh spark plugs(NGK). Added a bottle of seafoam gas conditioner (usually use STP gas conditioner but local auto parts stores advised I try this seafoam stuff) to a full tank when I pulled it out of storage. Been through three tanks of gas from different gas stations so water not an issue. Replaced fuel filter and it immediately idle good enough at home for me to re-set idle to original setting but acted up again as soon as I took it out on the ocean. Bulb stays tight. Several months ago I had dealer work on control box and engine ran fine for several trips after the service so I don't really think it is a control box/cables problem.<br /><br />To me it seems like it is not getting enough gas except at/near WOT. This seems to be the reverse symptoms of most peoples postings.<br /><br />Is this problem a simple do-it yourself or should I just suck it up and let the dealer service the engine and my wallet.<br /><br />Snapper season closes in just a couple more days and it's looking like I am outta action unless a fast remedy comes my way!

Re: Delayed holeshot and poor idle, but good WOT

Check the compression and spark, and possibly the fuel pump and the accel pump.<br /><br />Accel pump sounds like its the problem, or part of it.<br /><br />TMD

Re: Delayed holeshot and poor idle, but good WOT

I was having problems similar to yours where it idled rough in gear and died after a little while and was stumbling on acceleration but ran good at WOT. Turned the fuel/air mixture jets out (counter-clockwise @ 3/8 of a turn and wella..... she is a purrin again!!

Re: Delayed holeshot and poor idle, but good WOT

I have not tried it yet and I may have more sever problems ( have to run a compression check) but I am going to install fiberglass reeds .. better throttle responce and other good reasons .. I think I hae a cracked SS reed but not sure

Re: Delayed holeshot and poor idle, but good WOT

You need to figure out whether it is running lean at idle and off idle or rich. It is difficult to tell from your description. Get a spray bottle of premix and squirt some into the carb throats (or try choking it part way manually )while it is acting up. If it picks up it is running lean. Disconnect the gas line at the engine and see if it picks up when the gas in the carb bowls goes down. If so its rich. <br /><br />Lean probably means you need to check for air leaks in the fuel lines and probably rebuild the carbs with focus on the idle orifices. Rich may be either stuck carb floats or fuel pump diaphragm leak.