update 91 Merc 200 power loss

[MACSOUT]

Replaced both switch boxes and all 6 coils, problem is still there. It idles great but flatens out above 2000 rpm. &%@!#$ <br />Any suggestions appreciated

 

[The Marine Doctor]

Re: update 91 Merc 200 power loss

Possible bad fuel delivery problem or the highspeed stator is not working.<br /><br />TMD

 

[Kenny Bush]

Re: update 91 Merc 200 power loss

I second the stator....... Did you buy two switch boxes new? Man... I feel your pain. I did the same thing on my 300 Merc. Ended up replacing everything except wiring harness. Big bucks, but I have not had any problems with that beast in over 300 hours. Almost a $1000.00 in electricals though. Anyway, stay on it. Your motor is almost rebuilt/remfg.....

 

[MACSOUT]

Re: update 91 Merc 200 power loss

Thanks a bunch guys, I replaced the stator a few days ago which did correct idle problem but not the high speed. The only thing electrical that I have not replaced is the Timmer base, but it checks out ok. I won't let it beat me.<br />Thanks again

 

[The Marine Doctor]

Re: update 91 Merc 200 power loss

Have you checked for any fuel coming out of the carb throats?<br /><br />TMD

 

[MACSOUT]

Re: update 91 Merc 200 power loss

Thanks Doc, yes, I have checked for gas leaking out of the carbs and found none. It doesn't pop back through the carbs either as if it might be a reed. I guess I'm leaning towards putting a new timer base on, that should cover all the electronics. Thanks again I really appreciate your time.

 

[mellowyellow]

Re: update 91 Merc 200 power loss

try both of these:<br />pump the bulb and see if she picks up, then <br />disconnect fuel supply and see if any change.<br />agree, may be fuel related.<br />post results and good luck,<br />M.Y.

 

[MACSOUT]

Re: update 91 Merc 200 power loss

Thanks MY, and everyone, due to work, I didn't get a chance to mess with it untill today, and that was only for a couple hours. I had alread squeezed the ball durring the bog and there was no change however, when I pinched off the fuel supply, it did seem to get better, ie. had what seemed like normal reactions. So I thing we are on the right track. It just might be one float sticking a little in one of the carbs. I previously went through the carbs, did the tipical fill the bowl untill the float closed the needle and seat and everything checked good, but maybe there is a float sticking? I'll try again. Thanks for all the imput.

 

[MACSOUT]

Re: update 91 Merc 200 power loss

Gettin close, thanks to you guy's. I am no expert on these things by no means. I was an automotive mechanic for 30 year's and just trying to do the basics with 2strokes, (boy what a difference) anyway, had a chance to fool with it tonight for a couple of hours and replaced the last piece of electronics, the timer base, no help. All the electronics have been replaced. Here's the question, do you think it's possible for one float, (needle&seat) to shake loose enough during throttle up to flood during acceleration? <br />I really appreciate your input and if you need advise on automotive AC, Brakes, Engine problems, please let me know.<br />Thanks again.

 

[The Marine Doctor]

Re: update 91 Merc 200 power loss

Nope.<br /><br />The variance in fuel pressure is not enough for this to happen.<br /><br /> It is possible that one of the floats is set incorrectly or has a hole in it.<br /><br />I would take the carbs off and check the reeds..just to be sure.<br /><br />And check the recirclating hoses.<br /><br />TMD

 

[jim dozier]

Re: update 91 Merc 200 power loss

Check the fuel pump diaphragms if the carbs check out OK, particularly if you find the cylinder that the fuel pump is connected to isn't firing. A leaking diaphragm in the fuel pump can inject fuel directly into the intake port causing that cylinder to run rich and not fire properly.

 

[MACSOUT]

Re: update 91 Merc 200 power loss

Hey guy's, didn't forget about ya and wouldn't think about correcting the problem and not letting you know the outcome. I have been there before. The problem has been on my mind constant and thanks again for your inputs. I think it's more frustrating not being able to spend the time that I want to really dig in to it but just been super busy. Anyway TMD and everyone, I found this today. After spending the 9 bucks on the fuel pump kit, simple stuff but I am turning in to my worst nightmare of becoming a "Parts changer, and not a Mechanic". . I found that if I capped two fingers over the high speed venturies on the middle carb, and stab the throttle it would reeve up normally, ok it’s flooding, go through the carbs again and every thing is perfect. I called a marine mechanic at a local place here and explained everything and he told me to take out the BACK DRAFT JETS which as I’m sure you know are located in the little triangle section at the top and towards the front of each carb, (didn’t make sense to me) I did just that and reeves up like new, however idle went to garbage. <br />Thanks again for your input.

 

[MACSOUT]

Re: update 91 Merc 200 power loss

Hey Doc, finally got a chance to mess with it for a couple hours today. I did pull the "back draft jets" out and gave it an under load test, some improvement but still not there. It seems like there is less suction on the top Carb. ( not much but some) and cyl's 1&2 have less drop than the rest of the cylinders in Rpm's when pulling the plug wires off one at a time. I'm pretty sure on this engine that 1&2 are on their own chamber, 3&4, and 5&6, and sealed in between on the crankshaft. Am I thinking right? Anyway, I'm thinking maybe top crank seal or that top carb has a crack or something causing my problem. I heard of an ole trick about removing the flywheel, pouring some dish soap (enough to submerge the top seal) placing the flywheel back on and spinning it a few revs, remove and look for bubbles. Have you heard of that one. I think I'm going to try swapping the carbs to see if there is a change. Thanks again for your help