throttle body issue?

xjcj3a · Aug 31, 2012

1997 evinrude 115 intruder 60 degree motor.

awhile back i had some idle issues, it needed to be linked and syncd. motor now idles fine. but at 3100 rpms and below it has like a surge/miss issue. I rebuilt the carbs and made sure everything is at factory settings. Same issue under 3100 rpms. the mechanic is able to move the throttle bodie linkages around. telling him the throttle bodies are bad. but at 400 bucks a piece, thats alittle out of the price range. The mechanic is certain he can throttle body shim the butterflys to stop the air leak and it should last long after the motor dies. Im really frustrated at this point, does anyone have experience with this issue? thank you.

schematic · Aug 31, 2012

Re: throttle body issue?

kinda doubt the throttle bodies would cause the described problem.

I'm betting on mal adjusted idle mixture screws. People typically adjust mixture screws for best idle, but on this model you can't. You adjust for best off-idle to 3000rpm.

xjcj3a · Sep 1, 2012

Re: throttle body issue?

he said he adjusted carbs to factory setting of 4 and a half. i dont know anymore

Chris1956 · Sep 1, 2012

Re: throttle body issue?

The specs for a '98 115HP60* V4 call for initial setting of 5-3/4 turns open. The service manual recommends the idle mixture be adjusted for max RPM, while warm, in gear and in the water. Make sure the phillips screws on the callibration pocket covers are tight. Make sure the orafices are clear. Give them a blast of air or jet spray.

All of this is for a '98, but I would think your motor is identical.

xjcj3a · Sep 1, 2012

Re: throttle body issue?

the manual i bought says 4 and a half. I'm surprised the 98 would be so different. The motor was at almost 6 and a half when he got it. he messed around with that at different settings and it never seemed to work. He said he talked to a few of his colleagues and they said these motors are notorious for bad throttle bodies. it appears as if the previous owner knew this and put grease at the tops of the stems that hold the butterflys. I want to believe that this is the issue so i can fix it. Ive just ran into so many problems i dont know what to believe anymore. Im going to ask him to look the book over again and see what the factory screws should be set to. If thats messed with and the same thing keeps happening i guess try to shim. I guess i was hoping for someone who has had the same issue to pop on and say mess with the figlemawhosit. lol

boobie · Sep 1, 2012

Re: throttle body issue?

Are the cal pockets in the throttle bodies clean ??

xjcj3a · Sep 1, 2012

Re: throttle body issue?

I'm sorry i don't know what a cal pocket is. im going to move the mix to the specs listed above and try it again. how much play should there be in the throttle body ? i have quite a bit. i Just don't know if that's normal

Chris1956 · Sep 2, 2012

Re: throttle body issue?

Calibration pockets are the part of the carb that has the side cover on it. Remove the screws and give the idle passages a blast of Gumout....Replace gasket and retighten screws securely.

woody66912 · Sep 2, 2012

Re: throttle body issue?

Just a guess but is this thing stuck in quick start.

Try grounding out the white / black wire on the temp sender, after the engine is running, this will take it out of quick start. You should see a 3 to 4 hundred drop in rpm.

xjcj3a · Sep 2, 2012

Re: throttle body issue?

I took it out this morning and ran it alittle. The cal pockets are clean and I cleaned and moved the idle screws to 5 and 3/4. I have not been back to the ramp to move the screws but it still surged at 3100 rpm. In looking at this the butterflys have very little play in them. I can't imagine that's the issue.

At idle and low rpms it seems to be running sporadic and rough. Seems to be loading up. Running rich? Ramps are packed right now so hopeing to get out in the morning.

I adjust the screws while running at idle in gear correct?

xjcj3a · Sep 3, 2012

Re: throttle body issue?

took it out today, barely wanted to run at 5 3/4 turns. turned it in slowly and got better every time. i think its at about 4 1/4 right now. idles well, still alittle chop to it. Didnt notice the 2400 to 3100 rpm studder that was there before. Water was wind chopped today so couldnt quite tell. going to take it to a different ramp tomorow that is more sheltered and hopefully allows me to hear the motor better without the wind chop hitting the bottom of the boat.

Thanks for the replies so far, has saved me alot of money it seems.

xjcj3a · Sep 4, 2012

Re: throttle body issue?

Spoke to soon, same issues today. Now the motor idles at either 1100 or 900. Depending on what it wants to do it seems. The 3100 surge issue is still there but doesn't seem as bad. I cannot adjust the idle mixture screw anymore before the motor doesn't want to acelerate. Someone mentioned a quick start feature, what exactly is it what am I looking for?

Chris1956 · Sep 5, 2012

Re: throttle body issue?

Quickstart is a temporary automatic advance of timing when engine is cold. It shuts off when motor warms up or when you exceed 1200 RPM. If you do not have SLOW(strange), I doubt you have QS.

xjcj3a · Sep 5, 2012

Re: throttle body issue?

i probably do have the SLOW feature just not sure. would an intermittent power pack cause the 3100 studder? i just cant imagine this is fuel related anymore

schematic · Sep 5, 2012

Re: throttle body issue?

Stick a timing lite on it and see what is happening at idle and above. You'll easily see if QS is adding its 10 degrees.

throttle body issue?

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