84 Mariner 115 bogs out above 2000 RPM

[thunder]

I have a Mariner 115, serial #6527950. It seems to have no power at all above 2000 RPM's. The carbs are clean, timing has been adjusted, stator, plugs and wires have all been replaced. The stator checks out fine for resistance, as well does the trigger. (This according to the Merc Manual) It sounds like a timing issue, as the timing won't advance as the throttle is open. Verified that all carbs are opening the same amount. The high side advance is set to about 19 or 20 degrees. What could possibly be the problem? The compression has been checked, pretty consistant (high of 125 and low of 110). Could the switch boxes or coil packs be the problem? Maybe they're cutting out at higher speed. I need some input. I'm going to be putting the motor up for sale, and would like to have some idea as to the cause of the problem so I can tell potential buyers. Thanks in advance.

 

[dakk1]

Re: 84 Mariner 115 bogs out above 2000 RPM

Have you checked for spark at idle? If so, and you have spark, you could put an inductive timing light on each cylinder wire while running and see if your losing spark under load.<br /><br />Dave..

 

[webster101]

Re: 84 Mariner 115 bogs out above 2000 RPM

thunder my "85" did same thing but if I pumped the primer bulb at same time motor was boging took right off.allthow havent verifyed its fixed yet seemed to be to low fuel pump press(needed to replace fuel pump gaskets and valves)try primer bulb test good place to start.

 

[andy6374]

Re: 84 Mariner 115 bogs out above 2000 RPM

This sounds like a classic dirty carb problem. How do you know there are clean, did you disassemble and clean them or just inspect them. Just because they look clean on the inside doesn't mean a thing. I had the same problem as you before, and I swore I could have eaten off my carbs but....Gave them a soak in carb cleaner, more black sut poured out. I guess the smallest clog can bogg you down. After the motor ran fine and has ever since.<br /><br />You might want to test peak voltages of the stator. The high speed coil could be damaged and an ohm test is a start but can't tell the full story. <br /><br />Did you test for spark on all of the cylinders?<br /><br />Your compression range could be a problem, you want your values to be within 10%. That being said though, I don't think that is your problem.<br /><br />-andy

 

[fishingdan]

Re: 84 Mariner 115 bogs out above 2000 RPM

Check for spark on all cylinders before you do anything else.