1995 Merc 115 2+2 idle problems... need ideas!

[Watermann]

I'm in need some more ideas on my 1995 Merc 115 2+2 Ser#0G176502. Carbs cleaned, new gaskets and no adjustments made to floats. Fuel pump and accelerator pumps rebuilt. All fuel lines got new cable ties and bad lines replaced. Fresh non E fuel. Idle screws out 1-1/2, just waiting to get on water to properly adjust. Reeds inspected when carbs off and all are good and no fuel spitting from throats.

Below is a video of my motor running or trying to run.

Checking the FB Merc groups I found a video of the same motor with the exact same issue mine has...

 

[racerone]

Check compression first.-----Then test for good spark.----" good " spark is something that will jump a gap of 3/8" ( 1 cm ) with ease and with a snap you can hear.-----Oil injection in service and pumping the correct amount of oil into the fuel?

 

[Watermann]

140 - 141 compression across the 4 holes.
Spark tested the other evening with inline tester saw no lack of fire issues.
Cleaned out the oil tank and system of old oil. Ran motor on Pre-mix to get the oil pump/system purged of air.

 

[racerone]

Did this problem show up suddenly ?-----How did it run last season ?

 

[Watermann]

New to me motor, hadn't been on the water in at least 5 years by the hull decals of the old rotten glasser with a heavy duty galvanized trailer I got on the cheap. Of course the guy said it ran great when he had it out last.

 

[Superjetjim]

Subscribed

 

[racerone]

Perhaps you bought a problem motor. ----More trouble shooting is required.------Perhaps turn the low speed mixture needles on the top 2 carburetors out 1/4 turn at a time.-----You are aware that it only runs on the top 2 cylinders at idle.

 

[Watermann]

Perhaps you bought a problem motor. ----More trouble shooting is required.------Perhaps turn the low speed mixture needles on the top 2 carburetors out 1/4 turn at a time.-----You are aware that it only runs on the top 2 cylinders at idle.

Yeah that's the 2+2 moniker these motors have.

I'm through all the linking portion of the link and sync, just waiting for someone to help out with turning the key for me while I verify timing. None of the timing adjustments on the throttle arm are labeled as such so I'm thinking some goof may have screwed that up. No way I'm going to run the motor at 3k rpms on muffs to time it running as the book says to check max advance.

The only thing I found off that was troubling were the settings on the oil pump, it was set on the wrong line.

 

[Watermann]

Problem motor, not sure about that. maybe all of these models are? :lol:

This video is a different motor with the exact same issue, the one I found on FB. Let me know if it doesn't work.

https://www.facebook.com/video.php?v=10213565046947933

 

[Watermann]

Rough idle issue is solved, I went back to basics and did a Link & Sync. I have a PDF with the detailed instructions that I'll try to add to my section.

Take a listen...

 

[Watermann]

Guess maybe I can drop it here too.

 

[Superjetjim]

Glad you got it sorted. Mine idles like yours does now, nice and steady.

 

[Superjetjim]

Does your starter motor sound a bit like an old car horn when the motor doesn’t start, like a bit wheezy?

 

[Watermann]

Does your starter motor sound a bit like an old car horn when the motor doesn’t start, like a bit wheezy?

No the starter stays engaged just fine and doesn't make any odd sounds turns over great. It may be time for a new one, check out DB Electrical.