115 Mercury No Power for about 15 minutes

[jacksonplumber]

1988 115hp Mercury #OB260260 <br />I have only had this in the water three times.<br />I have new fuel premixed with Penzoil Marine Premium Plus 50:1. Motor is original equipment on a 1988 Stratos. The Motor Starts good and fast, I have a strong bulb. After leaving the dock I can not get the boat to go fast enough to plane. The engine sounds like the throttle cable is about half way. I sit in the water for a while with the fast idle pulled up or just drive around for about five minutes or more and try again and the darn thing just jumps up and flys. For the rest of the trip I have no issues and the thing does great through all throttle movement. I did also have this problem after stopped to fish for about two hours. I got out of the channel and pulled up the fast idle for a minute got back out and it jumped right up and full throttle all the way to dock (about six miles.)I pulled the fuel tank out when I bought the boat and dumped the fuel. (needed new bidge pumps)<br />Thanks<br />Stephen Reed

 

[Yepblaze]

Re: 115 Mercury No Power for about 15 minutes

Water in the fuel? Have you pulled carbs and cleared the float bowls of any residual water. That could take multiple attempts. Plus water can carry deposits that might take 15 minutes to get through the jets and passageways till they get used up and gas takes it's place and the carb starts workin. Sometimes it takes a while and like I said a bove more than one carb cleaning before you get all the goop out.<br /><br />You might suspect ignition component that starts working after the engine block warms it up.<br /><br />Look for a plug not firing when cold. By shorting the spark plugs out one at a time.<br /><br />Maybe the just a plug check will help point you in a direction. <br /><br />Once isolated do standard troubleshooting to isolate component.<br /><br />Perhaps you could try heating coil, switchbox, ect one at a time, with hair dryer till the cylinder fires off at idle. It should be noticeable.

 

[jacksonplumber]

Re: 115 Mercury No Power for about 15 minutes

thanks for response, I have ran about 20gal of fuel in it all new with clean tank. Which electrical parts would need to be hot to operate correctly? I have a manual and can check them. Motor runs good after ten minute warm up.<br />Also engine does not miss.

 

[Yepblaze]

Re: 115 Mercury No Power for about 15 minutes

If it had water in the fuel system it might take multiple tries at carb clearing, before you got it to quit appearing and settling out in the float bowl along with the water soluble goo it might carry. <br /><br />Usually the electronic components will fail when warmed rather than when cold but it's not impossable. I don't know your particular motor nor the exact component terms but the coils, and switchboxes might be generic terms to give you a direction to start on the electrical side.<br /><br />Don't forget the basics also, a spark plug and compression check.