Lunker777 Posted November 26, 2009 Report Share Posted November 26, 2009 Hey everyone .... I have a Mercury 18XD motor. Last weekend I decided to hit the water with a buddy. I launched the boat and when I tried to fire it up, it was a little stubborn.... finally she fired up and it was idling rough. When at WOT it ran great.... even a quarter throttle it ran awsome. Its just idling rough now. Im 95% sure it has to do with the weahter ( getting cold ) because I have read that you might have to tweak the carb. come the colder months. Well with the close of the season uppon us, I want to get out this weekend and give it one more try ! Just wondering if I could get some help for the more experienced motor guys out there ? Thanks for any help ! Link to comment Share on other sites More sharing options...
bigbuck Posted November 26, 2009 Report Share Posted November 26, 2009 Start by running some Seafoam through it. Have you changed the plugs recently?? Also, how old was the gas?? More than 3 months, it needs Stabil in it. Link to comment Share on other sites More sharing options...
Uncle Buck Posted November 26, 2009 Report Share Posted November 26, 2009 Motor needs to warm up... once it's warmed up it'll start and run like a champ... run seafoam through it also, it won't hurt it... Link to comment Share on other sites More sharing options...
jimmer Posted November 26, 2009 Report Share Posted November 26, 2009 I third the seafoam. That gas we have now really does a number on the outboards. I use it regularly now. I also had a problem last year and tried this, but it didn't fix the problem. I have a 25 Yamaha. I eventually took the carbs off and found a tiny sliver holding my float pin open. It would run like crap at slow speeds but great with the throttle open. One of the signs was some gas on the water surface after starting. Link to comment Share on other sites More sharing options...
Greencoachdog Posted November 27, 2009 Report Share Posted November 27, 2009 Motor needs to warm up... once it's warmed up it'll start and run like a champ... run seafoam through it also, it won't hurt it... After the motor warms up it should run well!... if it doesn't, you probably need a tuneup! Link to comment Share on other sites More sharing options...
fisher Posted November 27, 2009 Report Share Posted November 27, 2009 As discussed here many times, highest octane gas from Petro Canada, Esso and Shell do not contain ethanol and should be the only gas that you put into your motors. On those multi-grade pumps, I even go so far as to make sure the last person that used the pump before me also was pumping with premium gas so as to not get any residual lower octane gas into my tank. That involves roaming around a bit or just topping my truck with premium first, then filling the boat. Link to comment Share on other sites More sharing options...
Fish4Eyes Posted November 27, 2009 Report Share Posted November 27, 2009 (edited) As discussed here many times, highest octane gas from Petro Canada, Esso and Shell do not contain ethanol and should be the only gas that you put into your motors. On those multi-grade pumps, I even go so far as to make sure the last person that used the pump before me also was pumping with premium gas so as to not get any residual lower octane gas into my tank. That involves roaming around a bit or just topping my truck with premium first, then filling the boat. Higher octane=more heat. This is why I use low grade. Can anybody else vouch for using strictly premium on 2 stroke engines? Lunker777: if the sea foam does not help, I would clean the carbs and check for air leaks in the lines. Edited November 27, 2009 by Fish4Eyes Link to comment Share on other sites More sharing options...
fisher Posted November 27, 2009 Report Share Posted November 27, 2009 Higher octane=more heat. This is why I use low grade. Can anybody else vouch for using strictly premium on 2 stroke engines? Lunker777: if the sea foam does not help, I would clean the carbs and check for air leaks in the lines. Here is an article describing the issue with Ethanol, what to do about it and a lawsuit surrounding it's use and the effects on boaters. http://www.boats.net/Ethanol-Lawsuit.pdf Link to comment Share on other sites More sharing options...
perchslayer666 Posted November 27, 2009 Report Share Posted November 27, 2009 Your carburetor needs to be cleaned, simple solution man. If you are not so mechanically inclined to do it yourself, take it to a marine mechanic should cost around $150, but then she'll run smooooooth. Link to comment Share on other sites More sharing options...
Handlebarz Posted November 27, 2009 Report Share Posted November 27, 2009 (edited) Tyler I had some problems last season with my merc and Jim from Merrit marine said to choke the hell out of it on start up as they dont like to be cold at all since then I have used my choke full and keep choking it until it runs smooth on just the idle. also do you take you boat for a FULL throttle run after trolling all day? if not try that I know it helps me out after fishing 6-8hours on idle. See ya out there tomorrow we will be launching from the Creek not the light house. Edited November 27, 2009 by MrEh Link to comment Share on other sites More sharing options...
T Fisher Posted November 27, 2009 Report Share Posted November 27, 2009 First check your plugs check all hose connections for leakage always use Merc oil and only shell super gas. Guaranteed no additives. If that fails a compression test is needed clean your carbs Link to comment Share on other sites More sharing options...
Jer Posted November 28, 2009 Report Share Posted November 28, 2009 Higher octane=more heat. This is why I use low grade. Can anybody else vouch for using strictly premium on 2 stroke engines? Lunker777: if the sea foam does not help, I would clean the carbs and check for air leaks in the lines. I'll never use low-grade fuel in any of my small engines again, the ethanol is a killer. I don't know if higher octane burns any hotter, from what I understand it slows down the burn. In any case, I think the lack of ethanol in high-test far outweighs a little more heat. I've run nothing but Shell high-octane in my boat, lawn mower, weed-eater (all 2 strokes) this past summer and they have never run better. My Lawnboy had always been a hassle to start at times and continue to run rough til I was almost finished the lawn, with high-test in the tank, it starts first or second pull everytime and runs like a champ. Ethanol is death for small engines, especially for motors not run everyday. Link to comment Share on other sites More sharing options...
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