Plugs fouling while trolling

[apb]

I do quite a lot of trolling with the main motor (1999 Johnson 40 hp, oil injected, 2 stroke). Sometimes troll with a trolling plate down, sometimes not. When I do a lot of trolling without running the motor flat out for a while afterwards, I lose engine performance. Plugs fouling and such. Its not a problem on large lakes where there is plenty of room to open it up after a day of trolling plus there is additional wide open time getting to a spot and such. On smaller lakes there is not enough room to open it up and run for a while and I really don't want to mess with others that are fishing by running back and forth up the lake. Is there something that I could add to the gas to help clean out the motor when I do a lot of trolling? I have 2 tanks on board so it would not be a problem to just put stuff in the trolling tank.<br /><br />Along these same lines, I cannot seem to get the motor to run in low idle for any length of time. Engine dies on me. Is there something I can do to allow it to run in low idle well? If I could, it would mean that I could run without the trolling plate for most trolling applications. Or am I better off running with the plate anyway as it will run at higher rpms? <br /><br />I have also looked into getting a 4 stroke, either kicker or main engine, just not feasible right now. Appreciate any help that you can offer.<br /><br />Andrew

 

[oldboat1]

Re: Plugs fouling while trolling

recommend an older trolling motor -- not too large. The smaller troller (e.g., a 7 1/2 rather than a 15, depending on your application) can run at higher rpms and still provide a slow troll. Investment doesn't have to be too great, if you do the repair and maintenance yourself -- stuff that you can read about here all the time.

 

[newt]

Re: Plugs fouling while trolling

I am still new to outboards but not to 2 strokes. Does your manual give you spark plug options? I know with my 2 stroke motorcycle that a hotter plug was recommended if it was not going to be driven hard, and a cooler plug recommended for hard running. Maybe you will have better luck with a hotter plug?

 

[Dhadley]

Re: Plugs fouling while trolling

What plugs are you running? I know they are the "right ones" and probably "new" but tell us which ones. What about fuel and oil? What ratio? What octane and how old (specifically)?<br /><br />Good luck!

 

[apb]

Re: Plugs fouling while trolling

Thanks for the help! Will have to check the specifics on the plugs. Have changed them pretty regularily and always used what was there originally. For gas I've been going with the mid grades (89 octane). Been tanking up everytime I do out, so it should be new gas. Its oil injected so I do not control the mix on this. <br /><br />Andrew

 

[Dhadley]

Re: Plugs fouling while trolling

Good choice on filling up on the way out. Thats the best way. 89 is OK, but 87 is better. What brand of oil? <br /><br />Let us know about the plugs.

 

[apb]

Re: Plugs fouling while trolling

I've been using Quicksilver, Premium Plus 2-cycle oil (TCW3 certified). Plugs are champions, QL78YC are the numbers on the side.<br /><br />Andrew

 

[FlyBoyMark]

Re: Plugs fouling while trolling

Carburator adjustment for idle might need work too...87 octane has less additives than 89 and = less deposits. Try a higher quality gasoline ( "Ole' Buds" Brand ver. Mobile) Plug Heat is real important for trolling and what altitude are you running at?

 

[harrison20002]

Re: Plugs fouling while trolling

apb, I have never had this problem but a fishing buddy of mine has and he switched to a synthetic {?}, 2 cycle oil. He told me the bottom plug doesn't foul anymore while trolling. It may be worth a try. I hope this helps. Happy Boating, Hal

 

[Dhadley]

Re: Plugs fouling while trolling

Everything sounds good so far. The thermostat is still in, right? You might think about checking running temps at idle to make sure its not stuck open. Mark had a good suggestion about trying another fuel brand. I know it sounds silly but my 225 on my Hydrostream sure seems to like Amoco.<br /><br />If you pull the plugs when it stalls, do they both look the same or is one (bottom) cleaner than the other?<br /><br />Have the carbs been gone thru?<br /><br />Good luck!

 

[seahorse5]

Re: Plugs fouling while trolling

The Champion QL82C plugs may help, as they are one shade warmer than the 78's that you are using.<br /><br />Has the thermostat been inspected and the temperature of the cylinder head taken to see if the motor is warming up OK?<br /><br />Who adjusted the carb linkage and the idle mixture screws?

 

[seahorse5]

Re: Plugs fouling while trolling

From my previous post, the plug should read QL82YC. Sorry about that.

 

[apb]

Re: Plugs fouling while trolling

Thanks again guys! I'll try the synthetic oil, different gas and plugs and see what that does. <br /><br />Altitude is probably between 500-1000 feet AMSL. I have pulled the plugs on several occasions (one of the few things I do know how to do ) and they look the same. When I pulled them Sunday after fishing they were both somewhat blackened and had a little oil on them. Carb was adjusted by my mechanic. I take it in for service about every 100 hours. Other than real basic stuff (like add oil when needed or change out a plug), I let the mechanic do all the adjustments. <br /><br />Andrew