Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in gear

[jaxsearay]

First off, thank you to all who provide info on here to us less mechanically seasoned!
I have a Merc 3.0 w/ an Alpha 1 Gen 2.
I replaced the impeller with the Merc Kit. I feel 100% confident about the impeller itself, the gaskets and the internals replaced.
When I completely re-assembled I made sure the shift shaft lined up in the receiver from the upper.
I filled with new drive oil per recommended procedures.
I put on muffs, started up, let warm up and had lots of water flow out of the exhaust, better than prior to replacement job.
HOWEVER, when I attempted to place throttle into gear (both fwd and rev), there was an immediate clanking noise.
I stopped, put back into neutral, and shut off.
I believe my problem is somehow in the placement of the throttle at the time of removal of the lower. I've now tried several combos of throttle placement and prop/shift shaft placement at tim of re-install.
Should the shift shaft receiver from the upper lined up bow to stern when the throttle is in full forward?? - because it is.
If so, then do I need to simply line the shift shaft (bent elbow from lower) in a bow to stern manner and spin the prop to the left until I meet resistance? Then make sure that the prop does not spin at all (making sure the shift shaft doesn't pop out of gear)???

Thank you very much in advance!!!!

 

[oldjeep]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

You're putting it in gear on the muffs?

 

[hivoltg]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

If I had to guess you are a tooth off on the lowers shift spindle into the shift shaft. Its going into forward but not solid like it should. You can test each gear (f n r) with the motor off and spinning the prop by hand. If I had to guess you will have no reverse also. If you are certain its not a tooth off a small amount of shift cable adjustment will solve the problem. Been there before.

achris posted this video and it helped me resolve the issue:

 

[ktbarrentine]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

Yes...it will give you a good "clank" when going into fwd or rev while on muffs. I dont do this very often, but have done this test of my shifter before going to the lake after drive work.

The "first" check of the drive you should probably do after installing on the boat and before starting the engine on muffs is to to place the throttle in fwd (engine off), then go back and turn the prop CCW to make sure it "locks". When that is satisfactory, put the throttle lever in REV, and go back to the prop and turn it CW and make sure it "locks". Then back to neutral and you should be ready to put water to the muffs and start the engine. Generally there should be no need to "put 'er in gear" if you have done those pre-checks. I find this to be much safer, as I dont like the idea of a spinning prop in my driveway.

 

[jaxsearay]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

If I had to guess you are a tooth off on the lowers shift spindle into the shift shaft. Its going into forward but not solid like it should. You can test each gear (f n r) with the motor off and spinning the prop by hand. If I had to guess you will have no reverse also. If you are certain its not a tooth off a small amount of shift cable adjustment will solve the problem. Been there before.

achris posted this video and it helped me resolve the issue:

Thank you for the video!

 

[achris]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

Thank you for the video!

You're welcome....

 

[jaxsearay]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

Update: I've gotten lower back on by having the throttle in drive, lining up shift shaft and holding prop in place by wedging a piece of wood against prop and lower.
Oiled and tightened everything back up.
Put on muffs and issue seems to be resolved. Will put in water this weekend.
As stated originally, it wouldnt go into gear, well now it does, but when it goes its not a silent shift. It makes a bit of a clanking noise still as it is "grabbing gear".
I'm assuming the shift cable adjustment should resolve ??...
Thanks again!

 

[achris]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

No, that 'clunk' is normal. Just a manifestation of being a dog clutch.... We all got it and we live with it... It doesn't sound nice, I know, but it does sound normal....

Chris.......

 

[jaxsearay]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

The "first" check of the drive you should probably do after installing on the boat and before starting the engine on muffs is to to place the throttle in fwd (engine off), then go back and turn the prop CCW to make sure it "locks". When that is satisfactory, put the throttle lever in REV, and go back to the prop and turn it CW and make sure it "locks".

This is how the prop acts now. Thank you! When I spin the prop the opposite ways of the directions mentioned here, (i.e. throttle in fwd and turn prop CW) should the prop click???

 

[achris]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

When I spin the prop the opposite ways of the directions mentioned here, (i.e. throttle in fwd and turn prop CW) should the prop click???

Yes....

 

[jaxsearay]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

No, that 'clunk' is normal. Just a manifestation of being a dog clutch.... We all got it and we live with it... It doesn't sound nice, I know, but it does sound normal....

Chris.......

Gotcha! I do remember it existing prior to the work, but obviously now I'm more in tune with the inner workings in the lower and wasn't sure if it needed remedied.

 

[jaxsearay]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

Ok thx a bunch! ...you know the craziest part about this whole thing? ...the lowest quote I got down here for an impeller job was $600!! I bought the kit for $45 and some drive oil...then with a little research, some elbow grease and a little frustration later she's good to go!

 

[jaxsearay]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

You're putting it in gear on the muffs?

--------
You bet, but only momentarily for testing work done. What would the hazards of this be with general safety observed and no one/nothing around?

 

[oldjeep]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

--------
You bet, but only momentarily for testing work done. What would the hazards of this be with general safety observed and no one/nothing around?

The hazard is beating the crap out of the gear set since there is no water to buffer the gear engagement. That is why you are noticing the huge clunk.

 

[jaxsearay]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

Gotcha, didn't know that. Thank you for the heads up!

 

[jaxsearay]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

Ok! Soooooo..... put in the water this weekend and ran great! No clanks, goes into and out gear just fine! Best yet! ...UNTIL... I idled into the marina to get fuel.
Here's the story...We put in and fired right up. Ran WOT, 3/4 throttle, 1/2 throttle back and forth, no problems for about 25 minutes.
Then (looking forward to a nice day of boating), I figured I'd gas up. As I entered the no-wake zone and idled toward the fuel dock - all of a sudden (within about 20 seconds) the temp gauge went from 170-220 (maxed out), the alarm went off, I immediately shut down and floated to dock.
We sat and waited for about 20-30 mins for engine to cool and then idled back over toward ramp (200 ft away) once temp was back down in 170 range. Meanwhile it seemed like the temp wanted to shoot back up if given the chance and i didn't want to risk engine damage, so we pulled out.... frustrated to say the least...
ANY IDEAS?!?!
There wasn't anything clogging inlet holes, no debris wrapped around, drive lube was exactly where it was when we pulled out of the drive way, no tell-tale signs of anything. Haven't re-removed lower unit yet.

(History is: I changed the impeller 1 week ago. This is the first time out on water since impeller kit change. This is my first impeller change out as well. No prior history of overheating!)

Will run in driveway on muffs one night this week.

Almost seemed like the heating up may have been in conjunction with having the unit trimmed at a certain height??...

Thank you all!

 

[hivoltg]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

Pull the lower off, connect your muffs, and turn on the water. If you see any water coming out around the back of the impeller base, it needs resealed. There is alittle air weap hole on some of the impeller bases infront near the shifter. Water from it is ok. Exhaust gas will mix with the impeller water and overheat you if its not sealed.

PS water wont flow out the main impeller housing water tube during this test like you will expect it todo. That is normal and a good sign you have a properly sealed impeller and housing.

Next open the impeller housing back up and make sure the impeller locking key off the driveshaft is engaging and turning the impeller.

I also would pull off the main water line coming up to the motor from the outdrive and back flush water from the motor side through it to make sure its not clogged with something (with the outdrive still off).

If you want to be cheap and save your new outdrive oil, throw a coffee filter in a funnel and catch it back in the bottle. I cant confirm or deny I have ever done this.

 

[ktbarrentine]

Re: Merc Alpha 1 Gen 2 - Replaced impeller - On re-install makes clanking noise in ge

Wow....sorry to hear about your issues... sure puts a damper on an otherwise well-planned boating outing.
Since it seemed to be running ok for 25 minutes, my theory would be that you may have gotten a plastic bag around your intakes....and it went away after you turned off the motor. Trouble is, that's all it takes to burn up the impeller, so either way, you are into a drive split to check it out. If you've got the experience, you can probably leave the upper on the bellhousing and just remove the lower for this work (the reassembly can be the tricky part, making sure your vert-shaft seals dont get messed up, and your water tube properly engages).
(checking for the other typical blockages as previously mentioned is also a very good idea, as well)
Also.... running on muffs may or may not tell you anything about the impeller, since the flow from your hose may mask/bypass the bad impeller.... but, it might help you pinpoint other problems.
Good luck and keep us posted!