mercury 200 offshore feels down on power searched for info no luck.... help!

[speedbuggy67]

I have a 1990 proline 250 walkaround with twin 200 mercury offshore 2.5ltr motors. ONe powerhead is a 1993 one a 1990 the problem engine is a 1993 that ran fine at one point. For the last year i've had a problem that im unable to solve. I've read and searched this sight over and over finally i decided to post. THe story is i came home from a boating trip and after coming through a no wake zone Port motor seemed down on power after traveling roughly 17 miles. I have two spare merc 200 offshore powerheads purchased for parts both have a bad cyl. and i've been swapping parts to try to solve....
The issue i have can best be described as one motor feels like a 150 and other a 200. When trying to get on plane one tach races up far faster then the other. I have done a compression check, about 130 on all six cyl, i swapped all 6 coil packs with one of the parts motors, switched out switchboxes, even swapped the ONE stator i have as spare (did ohm test on both seemed within spec don't have a dva meter) The other spare and other motor have different stator/regulator setup so i can't try it. 2yrs ago when i got this rebuilt powerhead fresh i put on 2 new voltage regulators since the tach wasn't working. I do all my own work on the motors and hate to throw unnecessary money at them. I have also swapped fuel lines from p to S motor and no change The fuel filter/water separator have also been changed as well as the little thumb filter on the motor. I put my hand in front of all six throats of the carbs so i didn't feel a reed valve was bad since i got good suction and no spitting. The only thing i can think of is either i'm throwing a defective part after another defective part or maybe its a carb issue. With 10 micron filter (if i recall correctly) the carbs should be fine i thought. Any help or suggestions would be extremely helpful! THanks in advance. My mechanic was out of idea as well and he's sharp. His only recommendation was the stator...

[j_martin]

Have you read the plugs? Either too clean or too dirty is bad.

Have you gone through the link-n-sync procedure?

Have you disconnected any "advance" or "idle stabilizer" modules and tried it?

Wouldn't hurt to go through the carbs. Less than a c note for cost in parts.

hope it helps
john

[speedbuggy67]

as per recommendations on here i did disconnect the idle stabilizer from the switchboxes, i did change the plugs after this situation started which i failed to mention above i'll yank them out and take another peek. I'll do a search on link-n-sync im not familar with that. I've swapped about every part i could between motors except the stator/trigger/voltage regulators. I do run a little extra oil in the gas in case the oil injection doesn't work just right. Few local guys with high hour 2 strokes seem to swear by it with no problems. The plugs i use are the ones that don't have the metal arm (whatever you call it) like cars. I have roughly 100/1 mix in the tank plus oil injection workign. ONE more thing is when revved at the doc it seems more sluggish then the other motor so its not just under load.

[speedbuggy67]

one more thing, i threw the timing light on both motors and it seems to be around 22 degrees on both while cranking it... Timing light on each plug wire gets spark, unknown if its hot enough but its spark...

[j_martin]

Maybe too obvious.
Among other things, linkage adjustment would ensure that the throttle valves all open at the same time and fully at full throttle.

[speedbuggy67]

Checked the linkage yesterday and its opening all the way at full throttle, the stator i just swapped on (ohm tested ok but unknown if perfect was used...) and motor was stalling so i reclipped on the advance module for the ride home/docking and didn't stall again. I did lots of searching yesterday and today on here seems lots of 200 mercs blow through stators and switchboxes pretty often is this true? I'll check plug readings tomorrow.... and come back with an answer. port motor still lagging starboard engine on acceleration. I read when stator high speed winding goes bad you won't get over 2500rpms but i have twin 200's so it will get above 2500 of course the other engine "helps" it along... can a stator and switchboxes be tested off the motor? thanks in advance.

Scott

[speedbuggy67]

thanks for the help, after a year the problem is solved, i called cdi and they recommended disconnecting the 4 yellow wires going to the regulators thinking they were shorting out and sure enough i disconnected the upper regulator so i would only be working off the lower one and still have a tach to compare, and voila boat jumped on plane instantly.... i had spare regulators off a popped motor i bought for parts but its the old yellow potted orig style that i heard catch fire but its working for now. The odd part is the two regulators i put on were new since the orig ones i got with the boat were bad and tach didn't work. They were the black potted style i bought off ebay with number 8m0006034 1098 on them. i couldn't figure out what brand they were but they did have an extra ground wire which i believe is supposed to help the fire issue.

Scott

[j_martin]

The black potted regs are probably later merc ones. They are usually good. You got a bad one.

You should have tested them when you put them on. It's easy, you just disconnect the yellows one at a time, connect the tach to the one you leave connected, and see if everything works. Either one should raise the battery voltage when running and drive the tachometer.

[speedbuggy67]

battery voltage according the gauges both read little under the 15 mark probably 14. something. I feel replying to a problem on this forum is important in the search process. SO many postings and people never reply to the cure to their problem. HOpefully someone else can benefit from my issue. I did have a wingnut on the battery loosen (now locknut) so i heard potentially that can take out a voltage regulator. When i orig replaced one voltage regulator maybe it was possible the other bad one that was known to be bad ruined this one. I replaced that bad one maybe a month after. Both of those orig regulators tach wires wouldn't work my tach. Once replaced tach worked fine. Thanks again j martin... Sure was lots cheaper then throwing a new stator on the motor which was my next plan....