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1997 Merc 125 cold start issue

Posted By: txmasterpo

1997 Merc 125 cold start issue - 04/07/21 05:04 PM

My old girl has always been cold natured about starting....after she starts it's ok the rest of the day most of the time. Runs like a scalded [censored] ape. Carbs have been gone through, link and sync, oil injection long ago deleted, run non ethanol fuel with sea foam always......new plugs this year. I know this is a finicky 2+2 motor and always thought that was the culprit....any way to make it not be 2 cylinders down at idle and low rpm? Sometimes it floods and I am also not 100 that the electric key choke does anything. Any other ideas? Pat??
Posted By: Bradley McCaw

Re: 1997 Merc 125 cold start issue - 04/07/21 07:57 PM

Following this. Electric choke doesnt seem to do anything for me either always have to throttle fast idle to get over the flooding. Summer heat always makes it worse too.
Posted By: TritonRob

Re: 1997 Merc 125 cold start issue - 04/08/21 10:10 AM

I think the idle is just the nature of the old beast. My XR6 is the same way. Cold natured and doesn't like to idle for to long. At the ramp I have to push in the choke for about 10 seconds before turning her over and she'll usually fire up. As far as the idle goes I'm just like you. Carbs gone through, link and sync done etc. but some days she don't want to idle good at all. She seems to idle better when it's colder out. One thing about her though is she's dead reliable and will flat out scream at wot....lol
Posted By: txmasterpo

Re: 1997 Merc 125 cold start issue - 04/08/21 01:55 PM

Yeah, mine only seems to like wide open
Posted By: Dan21XRS

Re: 1997 Merc 125 cold start issue - 04/08/21 03:47 PM

Try messing with the trim angle while starting. I had one you had to trip the engine up and down while starting for the first time. After that it started on the first turn each time... Dan
Posted By: bronco71

Re: 1997 Merc 125 cold start issue - 04/08/21 03:51 PM

My old Black Max 150 was like that. After dealing with it for years and several carb rebuilds later I finally decided to change the reeds. The factory stainless reeds were not broken but they were weak and a little light could be seen around some of them. I replaced them with carbon fiber reeds. I also replaced the "bleed lines" on the block. One was clogged and 2 were broken. OMG it has never started this easy, idles so good and smokes way less. It is still cold natured but not nearly as hard to start. I have only had it on the water hose as I need to replace a soft floor but it sure starts and sounds better!
Not sure on yours but the old Black Max had a "idle stabilizer" above the carbs that helped when unplugged.
Posted By: txmasterpo

Re: 1997 Merc 125 cold start issue - 04/08/21 08:00 PM

Mine needs to be level to start....and I have some Chris Carson reeds on the way
Posted By: TritonRob

Re: 1997 Merc 125 cold start issue - 04/16/21 10:51 AM

Originally Posted by txmasterpo
Mine needs to be level to start....and I have some Chris Carson reeds on the way


Let me know if the reeds make any difference....
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