81 omc 120 loud ticking noise when engine gets hot

Hi guys,
I have been having this problem with my boat for the better part of the season. When im out trolling the motor stays around 110 degrees and the tick noise stays pretty quiet like a normal noise you would expect out of a motor this old. After i go to open it up and get load on the old girl it starts to tick real loud. Also when i open it up it doesnt have a problem getting up on plane but then it has no interest to rev over 3200 rpm +/- 200 rpm. From the searches i've done on the forum it sounds like I need to set my ignition timing and probably set the valve lash. What do you guys think? Please do not answer me with do a search as I have done all of that and dont need someone else to tell me to do it. Thanks in advance for your help.

Re: 81 omc 120 loud ticking noise when engine gets hot

scott11 said:

Hi guys,
I have been having this problem with my boat for the better part of the season. When im out trolling the motor stays around 110 degrees and the tick noise stays pretty quiet like a normal noise you would expect out of a motor this old. After i go to open it up and get load on the old girl it starts to tick real loud. Also when i open it up it doesnt have a problem getting up on plane but then it has no interest to rev over 3200 rpm +/- 200 rpm. From the searches i've done on the forum it sounds like I need to set my ignition timing and probably set the valve lash. What do you guys think? Please do not answer me with do a search as I have done all of that and dont need someone else to tell me to do it. Thanks in advance for your help.

Click to expand...

Ayuh,... Have ya Checked the fuel filters, 'n fuel condition,..??

Have ya looked at the spark plugs for condition, 'n color,..??

Have ya changed the points, set the dwell, 'n timin' this season,..??

Re: 81 omc 120 loud ticking noise when engine gets hot

Ya sorry I forgot to add that I pulled the tank out in the fall and completely drained all of the old fuel. I added a new in pump filter and an additional fuel/ water seperator this spring. I just recently changed the spark plugs with no change. The one thing i havent gotten to is the points. Im thinking if my problem is to do with that I would switch to electronic ignition. What is your opinion on that idea?

Re: 81 omc 120 loud ticking noise when engine gets hot

The ignition point system has been around since Hector was a pup and is still a very reliable setup. But most people tend to ignore it because if adjustment is needed they get all befuddled and end up screwing things up. Like the Kyocera printer guy on TV says, "It's really not that difficult!" Ticking has nothing to do with the ignition. It is likely a hydraulic valve lifter that needs adjusting. Lack of performance is likely due to a carb that needs attention, the boat is full of water soaked foam that can add lots of weight, the prop is wrong for the boat, and obviously tune up (ignition dwell/point gap and timing) are not proper. It may also be due to the fact that the throttle is not opening the carb butterfly all the way. Lastly, all of this stuff is covered in the "factory service manual" for your specific engine and outdrive. If this is the GM 120 engine, it has hydraulic valve lifters so there is no "lash" adjustment, but there is a lifter adjustment procedure. Lash refers to mechanical lifters. Lifter adjustment pertains to hydraulic lifers which maintain "zero lash" when properly adjusted.

Re: 81 omc 120 loud ticking noise when engine gets hot

The prop is the same as its always been which I had no problem with last fall. I am currently in Winnipeg for work or I would be tending to this maintenance as we speak. Sorry Silvertip that is what i meant when saying adjusting the valve lash haha. i recently downloaded the factory service manual so I would like to take care of this when I get home. I have never had to adjust ignition dwell or point gap timing so I was wondering if there was a write up on this? If its a big deal I wont screw with it.