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Outboard motor help

michael0584

michael0584

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I picked up a 1967 40hp evinrude to replace the 1969 25hp on my 1969 13 sport Boston Whaler. It hadn't run in awhile so I cleaned carb and put in a new float and gaskets etc. new water pump, cleaned points and got it running. It has a rattle in it and it's hard to tell where it is coming from. Seems kinda high up like flywheel. Flywheel is tight on the shaft and I can't find any cracks. I have pulled the plug wires off one cylinder at a time while it was running and it doesn't seem to affect the noise. It does increase with rpm. Has 120psi compression on each cylinder and runs great otherwise. Any ideas where this noise is coming from? Attaching a video so you can hear the noise.
 
It kinda sounds like the flywheel hits the starter drive,but I would think sparks would fly if that were the case..

It almost sounds like something in the cylinder is being crunched up--sure none of those shells didn't get in the combustion chamber ?.

I have seen thick carbon deposits flake off during a long storage,then cause issues upon start up too,on a few of my own small engines..

Could be a wrist pin or loose rod,maybe some needle bearings came out of the main bearings ?...doesn't sound like anything I'd venture too far from shore with,thats for sure!..:yikes:..

I wouldn't stand too close to that engine,just in case the flywheel is faulty...

I saw one on an old Briggs & Stratton a guy ran with no blower housing and something got stuck in the throttle linkage and it raced up to about 5000 rpms and stayed there a good 30 seconds--while the guy was attempting to get the throttle back to idle,the flywheel flew apart--one chunk bounced off his thigh,the rest imbedded itself in a thick deck post about 10 feet away,like a giant slug from a gun..

It was the magnet that was imbedded in the aluminum flywheel that came out like a missle,other chunks just flew a few feet and dropped to the ground..his thigh was bloody and some chunks were stuck in the flesh,but it was not a life threatening injury...I was lucky I was on the other side of the yard talking to his father when it grenaded!..
 
diesel4me said:
It kinda sounds like the flywheel hits the starter drive,but I would think sparks would fly if that were the case..

It almost sounds like something in the cylinder is being crunched up--sure none of those shells didn't get in the combustion chamber ?.

I have seen thick carbon deposits flake off during a long storage,then cause issues upon start up too,on a few of my own small engines..

Could be a wrist pin or loose rod,maybe some needle bearings came out of the main bearings ?...doesn't sound like anything I'd venture too far from shore with,thats for sure!..:yikes:..

I wouldn't stand too close to that engine,just in case the flywheel is faulty...

I saw one on an old Briggs & Stratton a guy ran with no blower housing and something got stuck in the throttle linkage and it raced up to about 5000 rpms and stayed there a good 30 seconds--while the guy was attempting to get the throttle back to idle,the flywheel flew apart--one chunk bounced off his thigh,the rest imbedded itself in a thick deck post about 10 feet away,like a giant slug from a gun..

It was the magnet that was imbedded in the aluminum flywheel that came out like a missle,other chunks just flew a few feet and dropped to the ground..his thigh was bloody and some chunks were stuck in the flesh,but it was not a life threatening injury...I was lucky I was on the other side of the yard talking to his father when it grenaded!..
Click to expand...
I'm kinda thinking a main bearing. Pulled the lower unit and took the plugs out you can rotate it by hand and find a spot where it makes a noise that I'm pretty sure is what I'm hearing. Ran it without the lower unit and it still makes the noise. At this point I think it's toast. I started tearing it down to pull the powerhead. Looks like I can get a used one on eBay for under $200. Not sure if mine is rebuildable but doubt I could do it for under $200
 
A friend of mine is into boating--I'm not because I cant swim..
He has a lot of stories about various boats he and other friends had,and the adventures he's had on the ocean here with them..

Years ago he got a 16 foot boat free,it had an Evinrude motor,it had sat 2-3 years in a guys yard since its last excursion..he got it to fire up and run in a few minutes of tinkering with it--then it started making "bad noises"--he had it in a 55 gallon drum full of water so he could run it a few minutes ..

After several minutes,the engine locked up,and he took off the lower end--it turned out there was a bad bearing in it,the engine ran fine with it off--so he went to a local "scrapper" he knew that always had piles of junk motors in his yard,and he found one nearly identical to his with a good lower unit..he swapped it onto his engine,and the next weekend he and his cousin went fishing off Plymouth Harbor in the boat..

About 3 miles off shore,the engine suddenly started making crunching noises,then a loud "bang",and they felt the boat stop moving,but the engine was racing --he shut it off,and tilted it upwards to see if the propeller hit something or fell off,busted a shear pin,etc--the entire lower half of the lower unit was GONE!..its still at the bottom of the ocean..:yikes:..
Evidently one little needle bearing fell into the lower unit out of the upper bearing--he told me it was a pain to install,the new bearings had beeswax holding the needles in place,and one must have escaped during the install..:doah:..

They had only one oar,and it was almost sunset--they were lucky someone else in a boat came along,and they were able to get their attention,they called the coast gaurd,but they said if no one was injured,to see if they could get a tow back to shore,they had another rescue mission in progress..he had to wait until 1 am,when a fisherman who knew the people in the first boat that came along,and gave them a tow back to shore..

I think the only place scarier to break down than on the ocean in a boat,would be in an airplane...no breakdown lanes !..:eek:
 
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