Logo
FULL SITE MENU

Possible Impeller Problem??? HELP!!!

A

ace3677

New member
Just took my boat out for the first time this year and after about two min on plane my engine made a very loud grinding/low screeching noise. I instantly shut the engine off and removed the dog house and saw that there was some smoke coming into the engine compartment from the main drive shaft in the lower unit. This tells me it is not an engine problem I believe. also I noticed the temp increased significantly but not to a dangerous level because I shut it down right away. Im thinking it is either the impeller or the gimbal bearing (just because of the noise). If anyone has any ideas or suggestions I would greatly appreciate it. Also this is on a 3.0 liter merc with an alpha one outdrive.
 
what is the oil condition and oil level in the drive? Pull he drive to check the bearing. noisy bearing would not increase the engine temp.
being low on oil could melt the upper gears
 
The oil level was full and in good condition as I just changed it the day before. I pulled the bolt and clean oil dripped out so I know that was in good condition. I did forget to mention the there was the smell of what seemed like either burned rubber or something similar to gear lube.
 
To be clear, you removed the top plug and some dribbled out? Then remove the drive and inspect the gimbal bearing
 
Last edited:
Correct and pulling the drive off is the next step for me. Im hopefully going to get that off today and get back on with what I find out.
 
Put it in gear and see if you can turn the prop by hand. With motor off and in driveway. Look in bilge for rubber chunks. Did the motor rev high when you heard the noise? Yes to any of those could be the coupler. If do, then you HAVE to pull the motor to change it .
 
No to all of the above. The rpms remained the same and didn't lose any power just made the noise and smell with the small amount of smoke. Now the big problem I am running into is getting the stern drive off. I have the lower unit off without a problem but the upper part simply wont budge. Im at a loss.
 
sounds like water in the bellows caused the gimbal bearing to rust up or it is severely out alignment.
reattach the rams, put spacing blocks between the top of the drive and transom , CAREFULLY use trailer button, adding spacers
 
Bt Doc, he said he had the drive out. I'm understanding correctly he's having trouble seperating the top and bottom to get to the pump.
To the OP, have you watched any youtube videos to be sure you have all the bolts out. On mine there's one up under a zinc.
 
DaveG55 said:
Bt Doc, he said he had the drive out. I'm understanding correctly he's having trouble seperating the top and bottom to get to the pump.
To the OP, have you watched any youtube videos to be sure you have all the bolts out. On mine there's one up under a zinc.
Click to expand...

"""""""""" Now the big problem I am running into is getting the stern drive off. I have the lower unit off without a problem but the upper part simply wont budge. Im at a loss. """"""""""
 
Sorry for the confusion I probably should have worded that better. I am going to have to try that suggestion in the morning and let you guys know if that works out and what I find. Thanks a lot.
 
Alright using the trim tabs worked great and got the stern drive off. I found that the bearing was rusted and wobbled so I know that is bad. The bad thing is the bearing came out with the shaft and, correct me if I am wrong, but I think it should still stay in the housing. Also I believe I am supposed to replace that bellow in there as well?
 
a gimbal bearing rusted to the input shaft tells you the bellows were leaking or you had a very high bilge level at some point. A well greased and rust free bearing will stay in the housing. When something like this happens, replace the shift cable and boot, main bellows and gimbal bearing
 
It took meca few hours and beer breaks to do all that. I had never fine it before. I had to get a couple specialty tools. Hardest part was getting the gimble bearing out. Also, making the shift cable adjustments would have been eafierceuth two people. ( getting in and out if the boat)
 
Back
Top