9.8 2008 Nissan/Tohatsu off-idle howl/screech?

[pvanv]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

Are you running the 7-pitch HT prop, or the 5-pitch HT prop? If you switch to the other pitch, you will probably move the trolling RPM out of the range where that whine happens.

 

[Traxion]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

It's a 5p. I'm going to try the 7p.

 

[simplystressed]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

It's a 5p. I'm going to try the 7p.

There has got to be a way to quieten it our a way to deaden thenoise

Pvanv is it coming from the manifold in your experience?
Its strange that it only happens on some motors.

what about the latest 2011/2012 run of them?

 

[pvanv]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

It's a 5p. I'm going to try the 7p.

That may put you at idle when trolling. Might be quieter, but you may "make oil", especially in cold waters.

 

[pvanv]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

There has got to be a way to quieten it our a way to deaden thenoise

Pvanv is it coming from the manifold in your experience?
Its strange that it only happens on some motors.

what about the latest 2011/2012 run of them?

Yes, it seems to be an intake harmonic. Yes, it's odd that it doesn't seem to happen on all motors. The cylinder head, intake, air box, and carb are identical since the start of the 8/9.8A3, dating back to at least 2007, so AFAIK, yes, this is still a current "condition".

 

[simplystressed]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

Had it out today with the new prop and again the noise is there. Go back to stock and its gone. Only seems to happen above idle to mid range RPM and it goes away. Here's a video

 

[Traxion]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

Great video. I get the EXACT same thing with my 8. Really can get you annoyed when you're trolling into the wind right at that RPM.

I ran the stock prop and had the howl, albeit less than the next prop I tried. Wanted to get trolling speed down so I went to the 5p 4 blade. Howl is more noticeable in that the motor runs in that range much of the time I am trolling. Like the 4 blade but the noise sucks.

Motor has made the noise since new and I'm now at the 200 hour mark.

Only thing I think one can do is find a prop that you can run the speeds you want to without getting into that range. Which could be tough!

 

[Davem3]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

I have a brand new one and have the same thing. I am going with Paul's answer on this one, and my cure is very very simple. Ignore it and turn the radio up

this is amazing that the motor is so quiet, that we all pick this up, and hey if this is the the only problem i ever have with this motor, then so be it.

problem solved, LOLOLOL

 

[simplystressed]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

What makes me wonder is that it appears on random motors even with stock prop. The noise to me is almost unbearable due to the pitch. Even a two stroke would be more tolerable. Just wish there was a fix aside from testing multiple props or replacing the motor.

 

[Davem3]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

I ain't replacing this motor for squat, for me it happens at 1/4 throttle on a stock 8 1/2 X 7 prop..............once i get a tach and a book from paul, i might try playing with prop sizes, but to me, it is a non-issue

 

[simplystressed]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

I ain't replacing this motor for squat, for me it happens at 1/4 throttle on a stock 8 1/2 X 7 prop..............once i get a tach and a book from paul, i might try playing with prop sizes, but to me, it is a non-issue

Stock for me is fine, but it probably depends on the size of the boat and the load its under at a given RPM.

I hear you, its a great little motor but if this can somehow be fixed it would make a big difference to me.

I'm still going to try a 4B 5pitch and a 4B 7 pitch to see what happens.

 

[Davem3]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

actually i am curious to see what happens how big and how much does your rig weigh ...........

i have a 14' tinner, about 900 pounds total weight ?????

 

[simplystressed]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

I'm pushing around 1600 or so.

 

[Traxion]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

Stock for me is fine, but it probably depends on the size of the boat and the load its under at a given RPM.

I hear you, its a great little motor but if this can somehow be fixed it would make a big difference to me.

I'm still going to try a 4B 5pitch and a 4B 7 pitch to see what happens.

From my experience prop changes don't matter, the noise will just come at the same RPM but different speed. The 5p 4B is great for trolling (what I use it for) but it moved the sound right into the speed range I usually run. So I would not count on it being a fix by any means.

 

[simplystressed]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

Just wondering if anyone had any breakthroughs on this lately

 

[Traxion]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

Nothing new. I just deal with it. Went back and forth to the stock prop, all it does is move where the sound occurs. It's annoying at times but I can't seem to get it to change one bit.

 

[Wolverine1206]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

I purchase a new tuhatsu 9.8 with the same noise. They tried everything to get rid of the noise changing the lower unit and changing the prop with 5 different ones nothing worked. Tuhatsu USA replaced the motor with a new one under warranty. Had it out the other other day same noise but not as bad. Really not sure what the issue is but annoying

 

[Traxion]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

Anyone get any further with this issue?? Intake related from what I can tell, mine is a heck of a noise at times. Strange to say the least, I know lots of guys with Merc Pro Kickers and none have this problem. Seems related to the Tohatsu and Nissan stickered motors. Is the airbox design the same between the different stickered versions?? Never paid attention.

 

[TOHATSU GURU]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

Not an issue really. I've listened to hundred's of this model and most people accept the idea that the engine is so quiet mechanically that the harmonic, belt noise or air intake noise is a non issue. And yes, the air intake is the same. The average Mercury owner is usually so thrilled that their engine is reliable that any whining about a minor noise is overlooked. That's not to say that it is wrong to ask about what the sound is.

 

[Traxion]

Re: 9.8 2008 Nissan/Tohatsu off-idle howl/screech?

Not an issue really. I've listened to hundred's of this model and most people accept the idea that the engine is so quiet mechanically that the harmonic, belt noise or air intake noise is a non issue. And yes, the air intake is the same. The average Mercury owner is usually so thrilled that their engine is reliable that any whining about a minor noise is overlooked. That's not to say that it is wrong to ask about what the sound is.

It's note a huge issue I agree, but yet I don't say "dang, my car is super quiet, except when I am cruising down the interstate at 2200 RPM". That would never be acceptable yet for some reason it is in the case of this motor. I've been extremely happy with the motor so far but am still disappointed in this fact. Enough that my next boat's kicker will be a Yamaha. Now that Merc and BRP are both using the Tohatsu motors that is the only choice. I know nobody who doesn't love their little Yamahas. Now just gotta keep saving the pennies for the new one LOL!