Last ditch effort

Smitty

Cadet
Joined
Jan 16, 2001
Messages
21
Hi all,<br /> For the record, I am not a mechanic and will try to described the best I can. First off, I bought a boat from a great marina who is trying everything to fix this problem. They will even let me trade it for another boat if I'm not happy. No complaints there! This is the problem: <br /><br />The engine is a Outboard 125 Mercury. Since I bought it, it has a real rough idle at 2000 to 2400 rpms. They have tried to fix it twice and each time the motor ran a lot smoother. But it still bucks pretty hard at the above rpms. They had adjusted the timing to new plugs. Someone on here mentioned that because it has 4 carbs, it's the transition point for them kicking in and I may have to live with it. The problem is this. Where I fish on Long Island Sound, the current is so strong that I have to maintain 2200 rpms to stay stationary without hitting anything. This is where the engine performs at it's worst. If I gun it from idle to WOT, It takes off like a rocket. The Marina knows that I'm posting here for help and they encouraged it for suggestions. They finally took it to a Merc specialist and he checked it out and said that's all they can do. I really love this boat but I won't be able to keep it for safety reasons because of the fishing conditions. Any suggestions, I will forward it to the mechanic at the Marina. I look at all the posts about mechanics and marinas and I guess I got real lucky so far with these guys. They have always listened to the problems and tried to fix it right away. My last question is this, someone else told me that the 2001 model does the same thing? How can this be? How do they sell these motors? I have always owned Mercs and love them! I just don't get it. Again, any help would be appreciated. <br /><br />Smitty :confused:
 

kev_79

Petty Officer 1st Class
Joined
Aug 5, 2001
Messages
355
Re: Last ditch effort

What the other guy was refering to is that the merc 100, 115, and 125 are 2+2 engines. This means that below 2000-1800 rpms, the engine only idles on the top two cylinders. The bottom two carbs don't have low speed circuits. Of course the 2000-1800 is variable, because it comes down to when the carbs pull enough vaccum to kick in the main jets. From about 1600-1900, my 115 runs a little rough, and almost acts like it is about to lose power, but when the bottom two kick in, you're off. Unfortunately, ther isn't much in-between, no matter how hard I try, I can't really run in the 2100 rpm range, because when they kick in, it's immediately up to about 2700, and if I back off, back to 1700. I've heard that they designed it this way to save fuel when trolling, and to make the engine easier to use at low speed for fishing. If the motor runs good wide open, and it idles good, and the only prob you have is some hesitation at about 2000 rpm, then I think you will have to get another, or deal with it that way. I hope this helps you understand how it works. Good luck, and tell us what you decide :D
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Last ditch effort

As long as you have that model engine, Smitty, you are going to have that problem. Replace it with a 90 or 115 EFI 4 stroke. You will be a lot happier with it.<br /><br />Red sky at night. . . <br />JB :)
 

Smitty

Cadet
Joined
Jan 16, 2001
Messages
21
Re: Last ditch effort

That's what I was afraid of. :mad: I only wish I could buy a new motor. I have a baby coming in 6-weeks. It's hard enough trying to justify the boat now! :D I have a good wife though! Anyway, I thank for your explinations. It has helped a great deal. If you may have any other suggestions, I'm listening. Thanks again guys.... :p <br /><br />Smitty
 

gboon

Cadet
Joined
Aug 23, 2001
Messages
8
Re: Last ditch effort

Could you use a lower pitch prop so that you don't have to run in the problem RPM range? Might have to watchout for over rev.
 

kev_79

Petty Officer 1st Class
Joined
Aug 5, 2001
Messages
355
Re: Last ditch effort

I believe George has the only solution. For fishing, pitch the prop down. 15 is about as low as you can buy I think, but watch that top end, your upper limit on that motor is 5250 and do not go over. I have heard many stories about broken cranks on these types. Not for sure why, but my wrench said merc said it was from over revving, and how the motor is designed. Good luck
 

corm

Lieutenant Junior Grade
Joined
May 12, 2000
Messages
1,241
Re: Last ditch effort

I'm with George, one size smaller prop will get you over the rpm range that is giving you the problem. The only motors that don't do this are the EFI motors. All others have a transition from the low speed jets to the<br />high speed jets.<br />One thing that could be checked or readjusted is the accelerator pump, it maybe bleeding fuel in to the motor when it is not suposed to. The switch from low to the high speed should have happened at your rpm.<br />...have fun...corm
 

Bluefish

Petty Officer 2nd Class
Joined
Mar 14, 2001
Messages
125
Re: Last ditch effort

Hey Smitty<br />Sorry to here of your problem :( <br />I'm on LI myself south shore G.S.B. anyway I was just wanted to know what shop your dealing with good ones are hard to find!!!<br />Good Luck ;)
 

Smitty

Cadet
Joined
Jan 16, 2001
Messages
21
Re: Last ditch effort

Hi Bluefish... The name of the Marina is MIDLAND MARINE in Portland CT.<br /><br />Looks like a trade in..... :mad:
 

Bluefish

Petty Officer 2nd Class
Joined
Mar 14, 2001
Messages
125
Re: Last ditch effort

Hey look on the bright side on a trade in now you know what will work best for you and you didn't get stuck,I bet alot of people wish they could say that.<br />Good Luck :)
 

Smitty

Cadet
Joined
Jan 16, 2001
Messages
21
Re: Last ditch effort

hehehehe... Talked to the dealer yesterday. Mercury is sending a rep out to check out the problem. This should be interesting. I'll let you know what they say.<br />Smitty ;)
 

TONY H

Petty Officer 2nd Class
Joined
Jul 2, 2001
Messages
115
Re: Last ditch effort

Oh sure, Bluefish and I were wondering about a good Long Island dealership and you come up with Conn.<br />I knew it was too good to be true. :) <br /><br />Let me guess, you fish in StonyBrook?
 

Smitty

Cadet
Joined
Jan 16, 2001
Messages
21
Re: Last ditch effort

hehehe... Sorry guys! I didn't realize you were talking NY. :D What can I say? Have any questions for the Mercury Rep who's coming just to take a look at my engine? What kills me the most, it's a 1995 and not under factory warranty. What more could a boat owner ask for. I think i'm still trading it in.<br />Smitty
 

scarchest

Cadet
Joined
Aug 31, 2001
Messages
27
Re: Last ditch effort

Smitty, I dont think you have to live with<br />this problem. 1st question is the dealer adjusting top 2 carbs in or out of water.<br />The carbs needs to be adjusted in water, and in gear. This might solve your problem
 

Smitty

Cadet
Joined
Jan 16, 2001
Messages
21
Re: Last ditch effort

Thanks... I'll ket them know of your idea. I'm bringing it in Tuesday. Thank you all for your suggestions.<br /><br />Smitty :rolleyes:
 
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