'94 120 V-4 knocking?

[musky1]

My fishing partner asked me about my "noisy" motor. Seems to have a rather regular "knocking" that is most noticable at idle or slightly above. I do not hear it at cruising speed or above. Other than a little hard starting after a week or so of non use this thing runs great. <br /><br />I never gave it a thought as this rig is "new to me" and my experience with OMC products is limited to my Dad's '92 30 hp 'Rude. That thing sounded like you brought the hardware store home in a bag. Absolutely the noisiest OB I have ever sat in front of. My 25 Yammy and buddy's 75 Mariner are in the "tuned sewing machine" class by comparison.<br /><br />Do I need to be looking for something? If so where do I start? Added a little extra oil to the tank gas with no relief. Hoping you will tell me it's not serious, but I don't even believe that.<br /><br />Thanks for your consideration.<br /><br />/mike

 

[DJ]

Re: '94 120 V-4 knocking?

OMC's are not inherently noisy. They were always considered the industry standard for quietness. If yours is, there is something wrong with it.<br /><br />Adding oil is not the answer. Answer these questions.<br /><br />1. When was the water pump serviced?<br /><br />2. When was it last decarbed?<br /><br />3. What is the compression on each cylinder?<br /><br />4. When was the last time the carbs were serviced?<br /><br />If the answer to all of these questionsis-dunno? You have some maintenance to be done.

 

[musky1]

Re: '94 120 V-4 knocking?

Hey DJ, There are some "dunnos" here as this rig was a recent acquisition. Sold as a "low hours" rig there have already been some issues with deterioration from non use. Water pump gets replaced today and decarb before the w/e. I will have to get a comp tester and get back. I do know that additonal oil is not the answer, was simply curious if it would quiet down with a little extra lube. As far as carb service, I really doubt that anything has been done to it outside of changing plugs and winterization since it was new. Guy I bought it from was a friend's uncle and while Donny took pretty good care of his stuff externally, I don't know that he ever took any time on scheduled maint and upkeep mechanically.<br /><br />I'll be in and out alot over the next month, but will have more definitive information next time I post. Thanks for the reply.<br /><br />P.S. That 'Rude of my Dad's never was a quiet motor, right from the dealer. He was back numerous times and finally tired of the noise and gas guzzling tendencies and went to a Honda.<br /><br />Thanks again.....<br />/mike