lower unit 91 force l-drive

[DAJUICE]

need some advise. i have a 91 maxum 120 hp force l-drive. i was told the impeller shaft is not turning and that is why the overheat alarm comes on. the only shop around here does not want to work on l-drives. if i was to replase the whole lower unit would that solve my problem.

 

[roscoe]

Re: lower unit 91 force l-drive

Gonna have a hard time finding a mechanic to work on it, finding spare parts, or finding a new drive unit.<br /><br />Who told you the shaft was not turning?<br />There is no such thing as an impeller shaft. The waterpump and impeller is driven directly by the driveshaft.<br /><br />Any Mercury dealer in the area? They made it, they will likely fix it if they can.<br /><br />Does the propeller turn when put in gear?<br />If your propeller does not turn, you have serious problems.<br /><br />Do you know the model number of the motor?<br /><br />The waterpump kit for most L-drive motors is<br /> Mercury part number FK1204-1 WATER PUMP KIT about $60

 

[DAJUICE]

Re: lower unit 91 force l-drive

i took the boat to olympic boat centers.They are the ones that service force engines. The mechanic took the lower unit off and i was told that the impeller shaft is not turning, and that's the reason for overheat alarm going off. I am not sure if the propeller turns when in gear, but i am inclined to say that it doesn't. last time i had the boat on the water is when all this happened, and if i remember correctly when the engine was on and the alarm would be on but the boat did not move when in gear, at first i thought it might be a broken shift cable.What does it mean if the prop is not turning?

 

[RRitt]

Re: lower unit 91 force l-drive

if your lower unit is shot, then don't bother rebuilding it. just hit ebay hunt down a good used one. you could buy five used ones for less than price of one rebuild. with a used one in hand, it should take 30 minutes to put on new water pump kit, and 2 hours to install onto engine. add in the time to remove old gearcase and you have a total time estimate.<br /><br />as far as impeller is concerned. there is no such thing as an impeller shaft. the impeller goes directly on driveshaft. it's possible that the woodruff key (a square peg that sticks into side of driveshaft) could fall out or be broken. then the imepller would spin freely and no water would be pumped for engine cooling. more common is for the rubber to get chewed up by sand, the housing getting pitted with corrosion, or the impeller blades deteriorated with age.

 

[DAJUICE]

Re: lower unit 91 force l-drive

thanks roscoe and RRitt. Just bought a rebuild lower unit, hopefully that fixes my problem, we'll see in about a week.

 

[mind]

Re: lower unit 91 force l-drive

how did you come out on this juice?<br />i'm having similar problems.