impellers

[wrh]

I have a merc 150 from the early 90's. Previous owner not sure the exact year, has "Black Max" on side. I'm trying to change the impeller. I have located what I believe to be all the bolts including the one under the torque tab that hold the lower unit on. However my question is how do I disconnect this shift lever I have read about in posts by other boaters? I believe it is what is keeping the lower unit from dropping. Thanxs.

 

[JB]

Re: impellers

Howdy, WRH.<br /><br />You need a manual before you work on any engine you are not experienced with and most engines you are experienced with.<br /><br />A $30 bux investment will save you more than that every time you use it and prevent a lot of misery.<br /><br />Most grizzled old wrenches who have been fixing engine X for 30 years still use the manual. Wonder why?<br /><br />Good luck.

 

[wrh]

Re: impellers

Thanks for the advice, however I live in a small town with no marinas and can't locate a manual for this engine, especially as nothing is open on weekends around here. So I have to shoot from the hip and take the best shot I can at it.

 

[kjpfish]

Re: impellers

i beleive disconnecting the shaft is not required on mercury. i have a 1981 mercury black max 200 hp. there is one nut at the front of the lower unit, two nuts on each side, one under the trim tab and it hould come off. it may be stuck with corrosion.

 

[BillP]

Re: impellers

A manual can be bought off ebay in 5 minutes and be overnighted or 3 Day Priority delivered to your house. <br /><br />I would have never figured out the shift disconnect on my mariner(merc) without the manual. On OMCs I could do it without a manual but not on the merc.

 

[Walker]

Re: impellers

There is no disconnect necessary on that Merc. The shift shaft mates with the lower unit shift shaft with a splined collar, much like the driveshaft and the crankshaft. The most difficult part is getting them back together with both the control linkage and the L/U in the same gear. Once you've done it a couple times it becomes easy.

 

[wrh]

Re: impellers

should I leave the prop on or take it off before I start pulling on the lower unit?

 

[sloopy]

Re: impellers

keep the prop of, if it falls you can ding the propellor.

 

[kjpfish]

Re: impellers

you should remove the front nut and rear bolt under trim tab first. then the two nuts from underneath. then remove the two nuts on the sides but you NEED to support the lower unit when removing the last two nuts so that the lower unit does not **** at an angle as that can crack your housing. when reinstalling if you bought a water pump kit you should have a plastic sleeve with it which fits in the pump housing to guide the water tube into the housing. also make sure the upper and lower shift shaft are lined up. for changing the impeller the lower unit should be in neutral so you can turn the drive shaft while pushing the pump housing down to get the impeller in, a little grease also helps. also a little grease on the drive shaft splines will keep it from corroding together in the future but

 

[kjpfish]

Re: impellers

you should remove the front nut and rear bolt under trim tab first. then the two nuts from underneath. then remove the two nuts on the sides but you NEED to support the lower unit when removing the last two nuts so that the lower unit does not **** at an angle as that can crack your housing. when reinstalling if you bought a water pump kit you should have a plastic sleeve with it which fits in the pump housing to guide the water tube into the housing. also make sure the upper and lower shift shaft are lined up. for changing the impeller the lower unit should be in neutral so you can turn the drive shaft while pushing the pump housing down to get the impeller in, a little grease also helps. also a little grease on the drive shaft splines will keep it from corroding together in the future but DO NOT get any grease on the top as it will have no where to go when you tighten it up.

 

[12Footer]

Re: impellers

Yours is "VolumeIII"<br /> Click for Repair Manual

 

[wrh]

Re: impellers

Success. The impeller is changed. It was as ya'll described. I can see the advantage of changing it yearly if just to keep the bolts free of corosion. Thanks Again, WRH.