merc. outdrive kills motor when shifted into forward??

[dave buckner]

new boater just finished rebuilding upper outdrive on '74 galaxy with merc 165 i/0. boat performed great other than one new quirk: boat shifts into drive at idle fine, but as more throttle is applied motor dies most of the time. after several tries, she will accept throttle and drive normally. reverse gear acts norm0to WOT is no prob in reverse. there seems to be no major problem with either motor or outdrive( as boat cruised all day after getting past idle) i have checked shift and throttle cables, and adjustment seems fine. adjusting shift cable to either extreme did not have an effect on problem. my clymer manual only helps to an extent as it covers so **** many models and doesnt give any info to identify my setup. i am thinking there is a clutch in the lower unit. i dont see why clutch adjustment would be affected by upper rebuild. would a shot cluth give me these symtoms all of a sudden? is there something else i may be overlooking? by the way i drained gear oil and it looks new, no water, gear parts , etc. <br /> this forum has been invaluable to me as a new boater and DIY'er mechanic. any tips are always appreciated. THANKS!!!

 

[dave buckner]

Re: merc. outdrive kills motor when shifted into forward??

additional info: shift linkage between upper/lower unit is lined up straight with throttle in forward. i didnt lube gimbal bearing , and i did hear some slight squeaking early in the day. u-joints are new.

 

[hondon]

Re: merc. outdrive kills motor when shifted into forward??

Sounds like it might be time to replace and update your lower shift cable.Go with the alpha cable that threads in from the rear.You will need to tap the bell housing if this conversion has not already been done ,but trust me ,it's worth it.

 

[Bob_VT]

Re: merc. outdrive kills motor when shifted into forward??

Two items come to mind. Gas (quality of the gas in the tank) and accelerator pump. Does it die with a single cough?<br /><br />There was a modification to the accelerator pumps from mercruiser for older models. W/O it would die upon take off. Old gas in the tank is also a cause. Try some octane booster in the gas tank and run the tank just about out. Do not use dry gas.<br /><br />If it occurs allot after a long idle then you are loading up the plugs and the bad gas could also be clogging the carb circuits.<br /><br />Bob (Been there!)<br /><br />It is almost a 470 trait!

 

[Dennis4b]

Re: merc. outdrive kills motor when shifted into forward??

There is a microswitch which kills the ignition while shifting to neutral, it is load activated i.e. when you shift to neutral and the gears are engaged the pivoting point of these 2 cables will push a microswitch killing the ignition just long enough to disengage the gears. <br /><br />If the shift cable to the outdrive is not moving smoothly for example this can be a load which will trigger the switch. <br /><br />Easiest way is to disconnect it for a testrun (it just grounds the coil). Shifting to neutral will be more difficult, but it will tell you straight away if it is the switch or not.<br /><br />When I had a similar prob with my 470 it turned out to be a rotten gasket in the carb leaking air (leaning the mixture), no probs at idle, none at WOT, only at the transition phase, about 1500-2000 RPM. Fixed that, now runs like a champ.

 

[denniz]

Re: merc. outdrive kills motor when shifted into forward??

outdrive shift cable...........