Logo
FULL SITE MENU

BB140A with noisy crankshaft

R

repco

New member
Greetings,
Finally launched the Repco this week after the usual maintenance and tuning of the BB140A here at the house. Ran for about one hour while I set the timing and adjusted the carbs and all was well. Got it in the water and it started with a loud whine/rattle from the engine. Got out my stethescope and it seemed like the noise was loudest at the crankshaft pulley. I took the timing belt off this afternoon and when turning only the crankshaft by hand I hear a loud clacking noise, like gears meshing. Never heard this before.
For the short time I ran it while it was making the noise it was otherwise running fine. Nice and smooth, responsive, and I had oil pressure.
This is a well cared for engine with only about 200 hours of use. The bottom has never been apart.
Anyone have any ideas as to what might be wrong here. Hate to have this be the end of the season!!

Thanks,
Jon
 
If you removed the timing belt, you have eliminated the camshaft and valve train, and also the counter shaft.
If the belt cog on the crankshaft is not causing the issue, then it only stands to reason that there is an internal issue.

I'd be pulling the engine and removing the oil pan.
 
I'm going to pull off the starter this afternoon just to eliminate that possibility. It was rebuilt last winter. Long shot but I will only take a second. Also, I will check again with my stethoscope to eliminate the transmission. Maybe sound is travelling along the crank.
I don't think I can lift the engine to get the oil pan off while the boat is on the mooring. If I have to do that my season may be over before it has begun.

Jon
 
..........................

repco said:
I'm going to pull off the starter this afternoon just to eliminate that possibility. It was rebuilt last winter.
These use an Electro-Magnetic kick-out style starter motor. Doubt this is the problem.
With the main Common cable disconnected, you can activate the electro-magnetic portion only to see if retracts correctly.


Also, I will check again with my stethoscope to eliminate the transmission. Maybe sound is travelling along the crank.
Ah... good call!
An even more likely suspect would be the PDS bearing. Use the stethoscope at the flywheel cover.


I don't think I can lift the engine to get the oil pan off while the boat is on the mooring. If I have to do that my season may be over before it has begun.
These are very easy engines to remove/replace. If so, separate between the engine and flywheel cover. Leave F/C attached.
Click to expand...
 
It was the starter!! The fork that throws the pinion forward had slipped out of it's slot. A little adjustment and we're back in business. Happy ending......

Jon
 
Thanks for your support. The first rule of troubleshooting, start with the simple stuff!! There was a voice telling me to keep looking because this engine is just too fresh to have serious problems. They have a reputation for being very durable. I'm relieved, the new timing belt is here tomorrow and everything will be back together and running by the end of the day. It's all good......

Jon
 
Back
Top