Stalling when shifting from fwd to reverse

[dfgtye]

I have a 1988 Merc 4.3 V6 175hp. The motor runs fine and starts everytime on the first crank. The carb was rebuilt this spring, as well as primary and secondary filters changed and a water seperator added. The idle is perfect at b/w 650-700 rpms. <br /><br />Here is the weird problem: The motor stalls when shifting from Fwd to Reverse, but only if the steering wheel is turned ( so everytime I try to back into my slip). With the wheel straight the rpms drop to below 300 for a second and it sounds like it's going to stall but doesn't. Its almost as if the shifter is passing through some type of stop switch for an instant when changing gears and there is just a bit more load on the motor when turning do to the power steering that prevents it from recovering. I've tried uping the idle 100 rpms and that had no effect, it still drops below 300 at the switch point. I've also tried changing gears slower, which also had no effect.<br /><br />ANY INSIGHT WOULD BE GREAT. I've missed my slip now about 10 times and its starting to give me a complex. Thanks, MJS.

 

[crazy charlie]

Re: Stalling when shifting from fwd to reverse

Shifting at a slower speed would if anything make it stall.The motor is supposed to do a momentary stall when going from fwd to rev or visa versa.If you shift too fast you stall,if you shift too slow you stall.you have to get the speed that you move that lever just right.It can be adjusted but most of the time it is the way it is being shifted that makes it stall.The rpms should not drop because you are turning the steering wheel.This should be addressed as well. Charlie

 

[lorax]

Re: Stalling when shifting from fwd to reverse

I've had the same problem. It seems like I can shift into reverse successfully about 40% of the time. The bigger the crisis the more likely it is to stall.<br />I think it's got something to do with a misadjusted shift interupt switch. The switch is suppose to cut power, momentarily, when you shift. It's located next to the two shift cables on the bracket that bolts to the starboard manifold/riser.<br />Sorry but that's about the limit of my knowledge. Hopefully some guru will chime in.

 

[crazy charlie]

Re: Stalling when shifting from fwd to reverse

Iorax,the interupt will always cut the engine at the moment it is most crucial.When it is not a stressful situation we shift the lever nice and smoothe.When we are in a tight spot and close to another boat we tense up a bit and get too careful with the shift and cause it to cut the engine at the most inopportune time. Happens every time Charlie