FORWARD SHIFT PROBLEM/ 77 merc.1150

Hi, this is my first question at this site. I have a 1977 seasprite w/ a 1150 mercury inline6 outboard on it. Boat has not been used for 3 yrs. Cleand it up, got it started. But when it is shifted into forward it makes a noise in the lower unit, that sounds like, slow gear teeth slipping, then it takes hold and spins prop with no more noise. does the same when shifting to reverse, but not as bad. I have changed the lower unit oil. it did not have this problem when last used. However, i have noticed a diferance in the control box lever. Like i have to push it alot further forward to speed the throttle up.
shift cable maybe ? or lower unit issue, yiks. I have never taken a lower unit off. Any thoughts or suggestions would be appriciated, PLEASE.
Its a great old boat, in good shape (trying to restore it) and runs like a bat out of .... when running properly. Thanks for listening.

Re: FORWARD SHIFT PROBLEM/ 77 merc.1150

Check the shift slider. Neutral should be in center of travel. Now push throttle lever into forward and see if shift slide moved smoothly or what. Did you have the cables disconnected? Did you have to force the MerControl and broke something?

Re: FORWARD SHIFT PROBLEM/ 77 merc.1150

Thanks for your response. Are you saying that when the throttle lever is in the neutral position, that it should be in center of the shift slide ? i have not had the cables disconnected. I dont think i forced anything (praying). As soon as it stops raining here i'll check the position on the shift slide. thanks for info. i didnt know that.

Re: FORWARD SHIFT PROBLEM/ 77 merc.1150

I cleaned up the shift slide and lubed it w/ marine grease. it moves easier. it doesnt make a grinding teeth sound now when shift into forward. but it does make a loud "clunk" and spins prop. do you think i should take it to a mech , and them check it out. there are some expensive parts in there (lower unit) i dont want to make it worse. there also seems to be grease or oil leaking out around the back of the hub.