Post Number: 38
|Posted on Monday, July 02, 2018 - 07:27 pm: ||
i think i have a knock in my 109. it only happened at higher speed and after we had it running for awhile.
could you all took a look at the video, sorry for the quality it was sent to me via text message.
here is the link: https://photos.app.goo.gl/Kvpt4ZVgDCThxD129
i was thinking about starting with a valve adjustment and an oil change. thoughts?
as always i appreciate your help and advice, its gotten me this far! which is way farther than i would be on my own!
Post Number: 978
|Posted on Thursday, July 05, 2018 - 09:21 am: ||
I tried to open the video but got a message that the format was not supported on my computer .
Have you tried using premium fuel?
Marine engines , unlike automobiles, are ALWAYS under the maximum load for the throttle setting. It's like going up a steep hill all the time.
And at high speed, you've got your foot "pedal to the metal" .
Some engines use water injection to help prevent knock at high speed - the high temperature dissociates the water molecule and provides fuel and oxygen.
But try the premium ( Octane 91) before you do anything else. You'll have to get the old fuel out first before trying the premium.
Post Number: 172
|Posted on Wednesday, July 11, 2018 - 12:47 pm: ||
I can see the video, but can't make out the sounds.
Does it sound like an ignition knock?
How have you timed the engine? (ignition timing).
There are no timing marks, so you can't use a timing light. You have to 'power time' these engines. At about 3/4 throttle or more you turn (advance) the distributor until you start to get some knocking (pre-ignition ping) then you back off a bit until the knocking stops.
Post Number: 39
|Posted on Tuesday, September 18, 2018 - 11:44 am: ||
I apologize for just now getting back to you guys. I had a mechanic look at it, it is ignition knock. So we are going to adjust the timing when at 3/4 throttle next time out.
thank you for the responses!