Mercury 50 Not Reaching Mid-High RPM's

[kocr]

Have a 84 model 17ft Bass Tracker Mercury 50. Water was in the gas according to local marine shop, wouldn't maintain a idle and hard to start. $520 later for a complete carburetor rebuild I took it out to the lake and it was still hard to start. Take it back to the marina, guy pops the top and says aha yes you had a fuel line getting pinched you should be fine. Take it BACK out to the lake, starts right up, idles great, I'm thinking good the problem is fixed. I ease into it and at full throttle I'm going about 1/4 speed. Will build to higher rpm's in neutral but not in gear. My dad looked at the linkage and says it all looks good to him. So here I am about to take this thing to the shop for the 3rd time. I'm telling them I'm leaving it this time until it's fixed as it should be. I think it's rediculous I payed $520 and still have a boat that takes an hour to get across a small lake. Does anyone have any ideas or tips? Things I should say to the shop? Boat starts right up, maintains idle, runs very smooth, does not miss, but at full throttle it's simply not even reaching half speed or rpm's. Any info is greatly appreciated.

 

[kocr]

Re: Mercury 50 Not Reaching Mid-High RPM's

PS. Shop put in new spark plugs, new fuel lines, did complete compression test, etc. on the engine.

 

[aussieflash]

Re: Mercury 50 Not Reaching Mid-High RPM's

Unfortunately it sounds like the Stator or even worse the Switch Box $$$.Very common problem when you go for throttle around 2500 to 3500 she sits down.If you have Merc manual it should outline all electrical tests.Before anything check all connections on Trigger,Stator and switch box.Your mechanic may have knocked something loose while eating his bologna sandwich.

 

[matth121]

Re: Mercury 50 Not Reaching Mid-High RPM's

I had a similar problem, not fully sorted out yet but i'm getting to full power occasionally. Turned out my staor was bad- the stator under the flywheel has low speed and high speed windings, the high speed is responsible for rpms from half to WOT, while the low speed handles the rpm range from idle to half throttle( between 2500rpm and 3000rpm i think). So if your high speed windings are bad, this may be your problem- have the shop test the stator with a DV meter or a DVA on a normal Multimeter and confirm it's putting out the right voltage. Good luck

 

[CharlieB]

Re: Mercury 50 Not Reaching Mid-High RPM's

Save yourself a LOT of money, buy a dva meter or a DVA adaptor for any volt/ohm meter, download the free Ignition Troubleshooting Guide from the Support pages of CDIElectronics

Follow the well laid out directions to test your ignition system yourself, and save the rediculous amount the shop is planing on charging you for doing these simple tests.

Also test your fuel pump, disconnect the fuel hose to the carbs, crank the motor with the Lanyard pulled OFF to keep the motor from starting. You want to see a strong pulsed fuel flow at leaast an inch out from the hose and the diameter of the hose, any less, order a fuel pump rebuild kit.

 

[kocr]

Re: Mercury 50 Not Reaching Mid-High RPM's

I appreciate the responses. Took it back up there today considering I've already payed over half a grand and it still don't run right. The first thing Barney Fife did is drain oil out of the lower unit and tell me it smells burned and signs of metal in it, then he started it and he said the prop has some wobble to it and something about a bearing, he said since it gains rpm in gear (and it did I heard it) but not in the water he thinks its the lower unit/prop. Him and the owner of the business were looking at and poking and messing with this and that as the engine ran, looking as dumbfounded as ever. I told them it makes no sense because I have not hit anything, and never had a problem going over 5mph which is about the top speed now. The owner didn't like my attitude and went in. He told me last time"If it aint right it aint right", in other words that they will fix it. Barney Fife goes on to look at me like I'm nuts when I mention the stator, saying that's got nothing to do with it. Then he says something about doing another compression test on it, I tell him you already did, before you did the carb rebuild you told me the engine is in great shape and asked if I wanted you to proceed and I said yes. I told him the engine is solid to look elsewhere. He said he is taking it out on the lake tomorrow. I'm anxiously awaiting the phone call in the upcoming days. I told him I'm no moron don't call me back saying the compression is bad all the sudden because you can't figure out the problem so you just make something up. I said then what, I have you rebuild the engine and have the same problem when it's all over, I don't think so.

 

[matth121]

Re: Mercury 50 Not Reaching Mid-High RPM's

wow, i think you need a new shop. To look at you like you're retarded after mentioning the stator, not testing it and telling you theres no way it could be the stator....... I started this stuff a few months ago and I already know for sure a bad stator can cause this problem. Good luck.

 

[aussieflash]

Re: Mercury 50 Not Reaching Mid-High RPM's

You may have been cannibalized.I've heard of this happening before.Take your working stator/switch box and put it on other customers repair.Then getting your business to fix crappy one they put on your motor.Negative thoughts I know,but it does happen.
Your symptoms point to Stator or Switchbox.Your not nuts,your mechanic is and I would never leave my boat unattended with that goose.