force 50 hp stalling low idle

zoe

Cadet
Joined
Oct 13, 2001
Messages
8
Will run at higher rpm, but will stall at lower speed. Thought it was a fuel problem .Brought the boat to the repair shop for a tune up .They said it was the switch box?For $70 an hour and a $235 part its probably still cheaper than me trying to figure it out.Does this make sense or are they bumping up the bill,a friend told me these guys wouldn't let me out for less then $500?I asked them if they could replace the part with Mercury they said it didn't matter it all came from the same place.I am not suggesting they are dishonest this repair shop has a good reputation. Not very knowledgable about boats so any help would be appreciated.Thanks
 

12Footer

Fleet Admiral
Joined
Mar 25, 2001
Messages
8,217
Re: force 50 hp stalling low idle

Hi,Tim.<br />These motors are somewhat finicky. It may be no more than an idle adjustment. You need to try this before taking it in. On the right (starboard) side of the carb is an unpainted aluminum cam that a plastic roller rides on. This roller can be loosened-up,and retightened, to give more idle RPM. There is a line scribed into the aluminum cam, and the roller should be centered at that line in idle. This is proper idle timing.But the roller is concentric, and can be turned without changing the idle timing,simply by loosening the screw,turning the roller,and re-tightening it.<br />On a related note: As this boat and motor are new to you, you may not have found the feature built in to your control at the helm,where you can rev it up in nuetral..This comes in handy,even on a well-tuned motor, as sometimes, they settle out low after stopping,and when you try to start,the engine wont Idle for jack!<br />To use this, pull the control handle out (towards you,and then forward,as if you were putting it in gear. Note, that the only thing to change is the throttle. But it wont go into gear until you return the control to the nuetral position, and back in (towards the water).
 

lonewolf5347

Chief Petty Officer
Joined
Jun 11, 2001
Messages
529
Re: force 50 hp stalling low idle

had the same problem last year on my force 120 hp .would not idle,turn out to be the stator.they also said first it was the switch box.the stator but out high @ low voltage.i tried everything to try to make it idle no luck.check @ see if all cylinder's are fireing .if you like you can get great prices on a switch box @ stator from www.seilermarine.com mike has the best prices on this item that i have seen.also take a ohm reading on the stator.that can tell you the high @ low side resistance.
 

zoe

Cadet
Joined
Oct 13, 2001
Messages
8
Re: force 50 hp stalling low idle

Thanks for the quick response.Boat is in the shop now.I learned about that neutral in a hurry at the dock. Started up okay but everytime I put it in gear it stalled.Put it in neutral revved it up dropped it in gear and on plane right away.Only problem I was drifting while I played and was now pointed at shore which was about 15 feet away. I'd like to say it was superior skill and reflexes but I think I was real lucky.Thought before I tried it again I wanted to know it would run.At least now I have an idea where to start and what they are talking about.The mechanic said the switchbox was bad and the cdi was good.Hopefully they checked all the electrical.So it is possible that the switchbox could have caused this problem? Tim
 

rogerwa

Commander
Joined
Nov 29, 2000
Messages
2,339
Re: force 50 hp stalling low idle

I'm not sure I buy this diag. This could be as easy as a plugged or partially plug idle corcuit on your carb. I had the same problem, the shop said it was the packs and I said whoa.<br /><br />I brought it home to find crap at the bottom of my tank plugging the pickup tube. I cleaned the carb and tank and she was good to go.. Seeing that your from the northern climates, your gas may have been in the carb since last fall and gummed it up if not properly winterized.<br /><br />If it was the pack, tell him you want to see the measurements he took to figure that out. Also, why would the switch pack work at higher speeds and not lower. My understanding, which may be faulty, is that these packs either fail or don't. Not much middle ground.<br /><br />Just my .02 worth..
 

zoe

Cadet
Joined
Oct 13, 2001
Messages
8
Re: force 50 hp stalling low idle

Thanks for the quick response.Boat is in the shop now.I learned about that neutral in a hurry at the dock. Started up okay but everytime I put it in gear it stalled.Put it in neutral revved it up dropped it in gear and on plane right away.Only problem I was drifting while I played and was now pointed at shore which was about 15 feet away. I'd like to say it was superior skill and reflexes but I think I was real lucky.Thought before I tried it again I wanted to know it would run.At least now I have an idea where to start and what they are talking about.The mechanic said the switchbox was bad and the cdi was good.Hopefully they checked all the electrical.So it is possible that the switchbox could have caused this problem? Tim
 

zoe

Cadet
Joined
Oct 13, 2001
Messages
8
Re: force 50 hp stalling low idle

I got to talk to an actual mechanic yesterday. He said that it was only running on one cylinder.He said that the switchbox is the cdi.I asked how it could run at high rpm he seemed surprised asked if it could get on plane.He said it was possible that it would run at higher rpm. They called me back today said I need a "tripper" because it was now missing in midrange , another $150 .I asked if this was it , he said that everything else looked real good . Does this make sense?<br />Thanks Tim
 

rogerwa

Commander
Joined
Nov 29, 2000
Messages
2,339
Re: force 50 hp stalling low idle

If I am not mistaken, you have a CDI or switchbox and two coils. If it is firing on one cylinder, is it the coil or the switch box.. Could be either. <br /><br />The thing he is referring to is the trigger. Again I am suspicious of this diag, but would like other opinions from the crew.. I believe you shoudl be able to positively identify a bad trigger by looking at and measuring the resistance of the windings.<br /><br />I also had a midrange 'bucking'problem. That was related to the idle mixture adjustment. It had to be a little richer so it could get the right amount of fuel before the high speed circuit kicked in..
 

zoe

Cadet
Joined
Oct 13, 2001
Messages
8
Re: force 50 hp stalling low idle

I got to talk to an actual mechanic yesterday. He said that it was only running on one cylinder.He said that the switchbox is the cdi.I asked how it could run at high rpm he seemed surprised asked if it could get on plane.He said it was possible that it would run at higher rpm. They called me back today said I need a "tripper" because it was now missing in midrange , another $150 .I asked if this was it , he said that everything else looked real good . Does this make sense?<br />Thanks Tim
 
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