'95 Mercury Force 120 Outboard Reverse Issue

[anglerslade]

I have a '95 Mercury Force 120 ELPT (Serial#: OE194296) on my Astro Boat that has basically been causing me issues the past two years. It had mostly been in the lower unit, I had to have the clutch dog and reverse gear replaced as well as the shift cam. Once all that was replaced, it worked GREAT for one time on the water, but then the following time and every time since, it starts up after about three times cranking it, goes into forward perfectly, but dies nearly every time I put it in reverse. If I try to rev it in reverse to keep it from dying, it will come out of gear altogether and start doing the metal clinking that it would when the lower unit was messed up. I had been thinking that the problem was still in my lower unit, but recently it has started dying like its out of fuel at higher RPM's, which makes me wonder if my fuel lines are messed up, or the fuel pump needs replaced or something along those lines. I've also wondered whether the carbs are gummed up. Would any of those things be causing it to stall in reverse as well as stalling at higher RPM? I appreciate any information anyone can provide to help me avoid taking it to the shop yet again!

[EuropeanAM]

You may have TWO separate problems here.

1. Potential fuel delivery problem. Before dealving into this TOO deeply, read through the following post, and ensure that ALL (every single) recommended item is addressed with OEM COMPONENTS ONLY: http://www.bbcboards.net/mercury-3-l...tem-first.html

2. Shift cable adjustment or gearcase problem. This will require that the gearcase be checked to ensure that it remains in NEUTRAL (with shift cable disconnected) when shifted to the neutral position. IF the shift mechanism tends to "jump" out of netural on it's own... there is likely a problem with the cam, the follower, OR THE CASE BOSS IS WORN in the shift shaft/cam area.

Note: Don't overlook the gearcase situation... this needs to be addressed before running the engine again (and if you paid to have it rebuilt... really should be looked at by the rebuilder).

[anglerslade]

Thanks for the response. It remains in neutral when the shift cable is disconnected. I haven't had any issues with it jumping out of gear except if I try to "floor" it in reverse to keep it from stalling. Even then, I think I worded it wrong, it doesn't necessarily "jump" out of gear, it will still be in reverse position, but will make the grinding sound between the clutch dog and the reverse gear I believe. It doesn't do that all the time, in those instances where I can shift into reverse and it doesn't die, I am able to up the RPM's in reverse without it grinding. The marine mechanics in my area just use muffs, and the problem only arises in the water. So it is never 100% when I get it back anyways and was hoping to take care of it myself. I'm pretty handy and have the repair manual, just want to make sure I'm chasing the right issues.

[EuropeanAM]

Since you have a repair manual... look up the shift cable adjustment proceedure, and perform it precisely as instructed.

Then see how it does.