Warm 2002 Merc 115 2 stroke dies during idle, under load

[hphock]

I have a 2002 (Ok the emissions sticker on the engine says 2002 and boat is an 02 but the engine tag says 2001) Mercury 115 ELPTO on my Nitro fish n ski. <br /><br />The Problem - (Im still new with outboards so bear with me) everything runs awesome until we throttle down after running the engine for a spell (5 - 10 minutes at around 3500 RPM). When we throttle down going into a no-wake zone or to pick up a skier, the engine runs very rough and almost always dies in idle. When I put the engine in neutral, and try to re-engage into idle speed, the engine dies. Once the engine dies, it will restart but die again when we engage the prop - sometimes it will even die without trying to put it into idle speed. It does not occur when I disengage the prop (keep in neutral) while giving gas – I am at a loss of correct terms since I’m still relatively new with an outboard.<br /><br />The only way for me to get past this problem is instead of putting the boat into idle speed, I get it started and give it lots of gas from the start.<br /><br />Things I know about the problem:<br />1. Doesn’t matter who is driving<br />2. Only happens when the engine is warm (run at higher RPMS over a period of time)<br />3. Typically only happens when you engage the prop to go into idle speed<br />4. Engine shakes and runs rough (kinda shakes the whole boat!)<br />5. Engine runs around 750 RPM<br />6. Engine sticker says the idle RPM in gear is 650 (that seems way low since it dies at 700-750)<br />7. Cold it idles out of gear around 750-800<br />8. To keep the engine running, I have to 'throw' it into gear (basically very briskly - I mean VERY - put it past idlespeed and very slowly throttle back to idle speed- keeping the RPMs higher)<br />9. It has cost me one alum. prop from drifting into the bank and the prop hitting mud – ok that’s just something I’m bitter about (trolling motor battery died earlier that eve)<br /><br />I also would like to find the appropriate service manual for this 2 stroke engine (My wife bought me a 4 stroke Mercury book – I love when she tries)

 

[Wellcraft 89]

Re: Warm 2002 Merc 115 2 stroke dies during idle, under load

Are you the orignal owner of this engine from new?<br />If so you know the maitenace that has been done!<br />We don't, tell us.<br />Sounds like its either dirty carbs or a air leak <br />or sparkplugs.Have they ever been changed?<br />Rich

 

[hphock]

Re: Warm 2002 Merc 115 2 stroke dies during idle, under load

No, I am not the orig. owner. I bought the boat from a dealer only about a month ago. The dealer said to bring it in but they have a 2 week back log. Parts would be free but I would pay the cost of labor. I am a hands on person so I was hoping I could remedy this myself, sooner and maybe cheaper.

 

[Coolmaker]

Re: Warm 2002 Merc 115 2 stroke dies during idle, under load

115 two strokes run on two cyls below 1200 rpm to save fuel, and 4 cyls above that. It may only be a carb adjustment needed.... The dealer can rectify this issue quickly.

 

[hphock]

Re: Warm 2002 Merc 115 2 stroke dies during idle, under load

This past weekend, I ran the boat without any stalls after it was warm. However, the idle in neutral was 1200 to 1400 RPM and in gear was around 800. While in gear @ 800 RPM, the engine ran very rough (shook the whole boat). <br /><br />I didn't do anything to the carberators. I did add some fuel stabilizer since it was getting close to the end of the summer boating season. IE Ill be running it only when I go fishing and not for skiing or swimming.

 

[emzle]

Re: Warm 2002 Merc 115 2 stroke dies during idle, under load

Nitro, I have the same motor. Do all this in the water, not with the muffs. Make sure your idle timing is set right. After that's set btw 4BTD to 2ATD,then adjust the carbs. Start with 1/2 turns backed out from lightly seated, top (#1)carb, then 2nd. Only the top 2 have idle adjustments. Make sure you have the recommended plugs. Once you get those right, assuming no other fuel issues, then it will run as smooth as you can expect from this motor. It really pays to have a manual too.<br />Mark