merc 100 2+2 1988

[aban_esox]

please help-this has been an intermittent problem since i bought this ob in '89 (new)and nobody has any idea what is going on.<br />the bottom two cylinders won't kick in over 1800 rpm as their supposed to. at some point they will and are sometimes fine for the rest of the day or will resort to firing on the top 2. i never know how it will go.<br />i have spent to much time and money on mechanics telling me nothing and after 12 years i'm losing it. please help if you can.<br />thanx

 

[12Footer]

Re: merc 100 2+2 1988

A couple questions about your engine.<br />Do those cylinders have their own carb?<br />How about coils? <br />Do you have any visable corrosion around the connectors or terminals?<br />Hang in there. If I can't help,someone here can,and probably has first-hand knowlage of a simular problem. Mine (of this type) was coil packs failing new outta the box,due an open caused by corroded contacts.<br />And that's about it,other than fouled plugs,<br />due to old fuel.<br /><br /><br />------------------<br />Water,water everwhere...And all I can catch is CATFISH!!!

 

[aban_esox]

Re: merc 100 2+2 1988

thanks for your reply 12footer;<br />in response to your inquiries-my ob has a carb for each cylinder and also a coil for each cylinder.<br />all terminals are clean and free of corrosion and i've replaced plugs several times each season because of this problem and new plugs have never been a cure.<br />i start with fresh fuel each season and have done extensive winterization every year.<br />is there a computer brain controlling the firing?<br />could a fuel filter cause this problem?-although i've had this problem since dayone.<br />i look foward to hearing from you!<br />esox

 

[ODDD1]

Re: merc 100 2+2 1988

Esox, there is an accelerator pump on the side of the engine by the carbs....its job is to shoot fuel into the LOWER 2cylinders on acceleration...if the pump or cylinder check valves are bad the engagement of the lower 2 cyl will be inconsistent....setup/ link and synch are very important on these motors...alittle off an they wont run right.

 

[Little Bear]

Re: merc 100 2+2 1988

Esox,<br />I have this same motor (89')On my motor there was a recall in 1990 on a faulty switch box. Maybe yours was part of the recall. Mine ran poorly until these componets were changed. Now it runs like a top.<br />Good Luck,<br />Little Bear