Clanking noise

"After hitting a sand bar at w

"After hitting a sand bar at wide open throttle my Tohatsu 40d has a clanking noise. The noise happens in forward and reverse but not in neutral. I couldn't tell exactly where the noise is coming from even after putting a broom stick to my ear everywhere but it did not sound like it was coming from where the gears are. Can't see any damage to the gears, there's not metal in the gear oil, the prop shaft is not bent, and neither is the driveshaft, (put a straightedge on both). With the lower unit and water pump removed, I stuck the upper end of the driveshaft into an electric drill and spun it in forward and reverse and the noise was not there anymore. Since the noise is only there when the lower unit is attached to the running engine, I figured for sure something broke in the engine even though the engine sounds normal in neutral and even when you rev it up, so I took the whole engine apart except for the crankshaft assembly and still didn't find any sign of broken of bent parts, put it back together again and runs the same of course and still has the clanking sound. It has about 10% of the power it used to have when pushing the boat. A new prop and water pump were installed. This is a big mystery to me and I would greatly appreciate any ideas."

"If there is truly no noise wh

"If there is truly no noise when in neutral then it has to be a gearcase issue. Everything spins in either in gear or out of gear, except the lower gear case. I would look closer there."

"Rollie Rose: I knew that eve

"Rollie Rose: I knew that everything spins down to the pinion gear whether in gear or in neutral but when I did that test spinning the drive shaft pretty fast with an electric drill and didn't hear the clanking sound anymore, it threw me off track to tearing down the engine. It took somebody else to tell me what I should have realized, that of course it doesn't matter what's spinning the driveshaft. Thanks for being so diplomatic about it. I feel like Jonathan Winters when he found the Big W. It doesn't matter anymore but I still don't understand why the clanking noise wasn't there anymore with the drill though. At least I did a real good job putting the engine back together again. I will take a closer look at the gear box, thanks."

It may be as simple as the pro

It may be as simple as the prop blades may be pushed back enough to be clipping the cavitation zinc..if that engine has one.

"Rollie Rose: The prop isn&#3

"Rollie Rose: The prop isn't hitting the cavitation zinc. I think you were right from the first and the problem is the gear case cause there's no way that the load that the gears put on the engine which isn't much at all when the prop is spinning in mid air would cause it to make a clanking noise and not make one when in neutral. I said that I put a straightedge on the driveshaft but I failed to say that it was without pulling the driveshaft out and I know there is a driveshaft bearing in between the pinion gear and the water pump that you cant see unless you pull the driveshaft out which I will do before I take it to a dealer one of these days. I figured that if the driveshaft was bent in between the water pump and the pinion gear that I would see the effect of that bend when I watched the pinion turning the gears and that the gears would show some wear cause the driveshaft was bent but maybe that's something you can't see. Didn't have the special tool to pull it out. Right now I've got to leave the repair for later. If you got any more ideas I would appreciate them, if not I will post the outcome later. Thanks."

"The water pump had to be remo

"The water pump had to be removed to spin the driveshaft with the electric drill which resulted in no clanking noise either in forward reverse or neutral. Is there any possible reason the clanking noise would be there only when the water pump is installed and when the driveshaft is turned by the engine as opposed there being a clanking noise with the water pump off and the driveshaft turned by the drill? Maybe I should pull the driveshaft out to take a look but maybe there's no need to buy the special tools and do work if there's no chance anything is broke or bent in there. Also I had said there wasn't much of a load put on the engine for it to be making the noise with the prop spinning in mid air, but I was wrong because that was with the drill spinning the driveshaft with the water pump removed. With the water pump installed and the engine spinning everything, then the water pump itself puts more of a load on the engine. I still think though that the noise has got to be coming from the lower unit since the clanking noise is not there when in neutral and the engine sounds normal."

"Get a $3.00 engine stethoscop

"Get a $3.00 engine stethoscope and run it down from the engine to the lower unit. When the noise becomes "sharp" you have located where the metal is binding...It has a 99% chance of being in the lower unit based on what you have described. However, you can get a harmonic resonance from a bearing failure on the crank that seems like it is coming from the lower unit."

I will get the engine stethosc

I will get the engine stethoscope then post the outcome here in a couple of weeks. Thanks for the advice.

"To: Tohatsu Guru and Rollie R

"To: Tohatsu Guru and Rollie Rose who tried to help me. Found the clanking noise and am posting it just in case you were wondering and also there's a small chance somebody else can be helped sometime. Hit the sandbar, tore up the prop so I bought a new prop online. The testing by spinning the driveshaft with the drill that resulted in no clanking noise must have all been done with the prop off and hearing the clanking noise was with the motor running and the new prop on. I didn't see any reason to think there would be any difference out of water. The Hustler Propeller from Turning Point was according to them the correct one, but where it butts up against the thrust washer there is a recessed place in the hub assembly where the protruding lip of the thrust washer is supposed to fit tightly and be the same diameter of the recessed place but it is not. The recessed area is about 1/8" bigger diameter than the lip of the thrust washer. This hub assembly is a plastic tube that comes separate and you have to slide it into the prop where it locks into place. Also the splined area inside the prop is only about 1 1/2" long at the nut end of the prop. That's not long enough to keep the prop from wobbling a little and clanging against inside of the exhaust housing of the lower unit where there's not much clearance if there's not a tight fit around the lip of the thrust washer on the other end. It's hard to see with the prop spinning. The guy at Turning Point replied immediately to 5 straight emails but was not a Technician. There's no mention of any adapters in the instructions that came with the prop and none came with it. Don't know if it is a design flaw or they sent the wrong hub assembly tube. Turning Point is sending me a new free thrust washer to see if will fit but I think I'd rather have a different hub assembly tube. Thanks. ps Do you know how the wiring to my kill button is supposed to be? I can't tell by the wiring diagram which I have. I had the wires marked with tape but it fell off."

"So the problem was the after

"So the problem was the after market propeller...There's a lesson there. The kill switch is color coded. Black to black and brown to brown. So simple a cave man could do it...If he wasn't color blind "

I know that's right. Than

I know that's right. Thank you sir.