1973 Merc 850 stiff throttle no cables attached

[Sirenig]

I have a 1973 Glastron with Mercury Thunderbolt 850. I've pulled the motor from the boat to more easily work on it. The cables, which I'm replacing, have been removed. I am unable to rotate the throttle linkage. It's extremely stiff. I can grab the distributer cap and rotate it somewhat, but that's about it. The engine turns over with 155 compression readings on all four cylinders.

 

[catfishr1]

Re: 1973 Merc 850 stiff throttle no cables attached

Hi Sirenig: When I first purchased my supersport, it had a 1973 85 h/p merc on it. Same problem I think? It had sat inactive for awhile. I found the problem to be grease in base of distributor. If you look , should have a zerk on dist. grease until you have flushed old grease out. Hope this works for you, did fer me.

 

[Chris1956]

Re: 1973 Merc 850 stiff throttle no cables attached

In addition to what Catfish said, there is a locknut on the throttle arm bolt. Maybe you can loosen it. Push open the carbs, using the lever where they meet the distributor arm on the top and see if they are stuck. It has been known to happen, especially if the motor was sprayed with that corrosive dry chemical from a fire extinguisher.(don't ask)

 

[Gomer50]

Re: 1973 Merc 850 stiff throttle no cables attached

I agree 100% with the above,I can almost say for certain the distributor hasnt moved in awhile (dry grease) causing it to bind.Either a good cleaning or as stated above there are 2 zerts and give a good charge of new grease.

 

[Sirenig]

Re: 1973 Merc 850 stiff throttle no cables attached

I've pulled the distributer. Fully cleaned and put in fresh grease. It works perfectly. It must have been the dry grease. thanks for the response!