Yamaha T8 vs Yamaha T9.9

Thrasher_1

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Jun 2, 2009
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Curmudgeon
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I recently sold my T8 and hung a new T9.9 on my NR Seahawk and have noticed some differences, I think. I was curious if any of you have changed over and if so, have you noticed any of these, or others?

I have it hanging on the same side as the T8 was (port). Now when turning port side, most of the time, it takes it forever to turn the boat and especially turning around at the end of a troll. I never had that issue with the T8 as I am now with the T9.9. Now, I am having to walk inside and assist the turn by turning my main and using it as an assist rudder. Turning starboard is business as usual.

Next, throttle response with the TR1 isn't as quick as with the T8. It seems like it takes a bit for it to RPM up and down depending on what I am asking of it. Also, this 9.9 may have a higher HP rating but it doesn't appear to have as much thrust as the T8 did. That T8 was very positive on course adjustments and especially turning around.

Finally, (and I have already talked to the dealer about this one and they talked to me about a fix). You can hear the RPMs fluctuating up and down throughout the troll. It doesn't stay constant. After a couple of minutes it surges upwards in RPMs. This is thought to be due to how lean they come from the factory.

So far, I am not impressed with this motor. Anyone have any feedback on theirs?

Thanks
 

Salmon Addict

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Feb 5, 2011
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I used to have a 4 stroke Evenrude kicker turned the boat really good. Then I replaced with 9.9 Yamaha same extra long foot now it won't turn unless the main is all the way out of water.
 

Thrasher_1

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I used to have a 4 stroke Evenrude kicker turned the boat really good. Then I replaced with 9.9 Yamaha same extra long foot now it won't turn unless the main is all the way out of water.
Which I don't understand why that is...
 
W

woodrow246

Thrasher, dont have much for ya on the steering issue as i have the main and kicker tied together..works well. I did have an RPM fluctuation the first time i ran it, after running it hard the first trip out it hasn't done it since..Break in issue I assume..The 8 hp yammy I had on my lund was tied to the main also so sorry no info on the steering issue..
 

dragonballs

I'm off probation
Mar 28, 2008
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Vance
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t 8 still more thrust and reliable motor.. glad I still have mine...
 

Wild Bill

Drinking the Suzuki Kool-aid and liking it!
Aug 4, 2010
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I recently sold my T8 and hung a new T9.9 on my NR Seahawk and have noticed some differences, I think. I was curious if any of you have changed over and if so, have you noticed any of these, or others?

I have it hanging on the same side as the T8 was (port). Now when turning port side, most of the time, it takes it forever to turn the boat and especially turning around at the end of a troll. I never had that issue with the T8 as I am now with the T9.9. Now, I am having to walk inside and assist the turn by turning my main and using it as an assist rudder. Turning starboard is business as usual.

Next, throttle response with the TR1 isn't as quick as with the T8. It seems like it takes a bit for it to RPM up and down depending on what I am asking of it. Also, this 9.9 may have a higher HP rating but it doesn't appear to have as much thrust as the T8 did. That T8 was very positive on course adjustments and especially turning around.

Finally, (and I have already talked to the dealer about this one and they talked to me about a fix). You can hear the RPMs fluctuating up and down throughout the troll. It doesn't stay constant. After a couple of minutes it surges upwards in RPMs. This is thought to be due to how lean they come from the factory.

So far, I am not impressed with this motor. Anyone have any feedback on theirs?

Thanks

Are you sure that it is not the Tr1 that is causing your woes. When throttled up The ram on my tr1 has trouble overcoming prop torque and therefore the boat it not as responsive when turning to port. Starboard turns are no problem. The thrust difference between those two motors should be quite minimal unless something is wrong with the 9.9.
 

Thrasher_1

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Are you sure that it is not the Tr1 that is causing your woes. When throttled up The ram on my tr1 has trouble overcoming prop torque and therefore the boat it not as responsive when turning to port. Starboard turns are no problem. The thrust difference between those two motors should be quite minimal unless something is wrong with the 9.9.
I put the TR1 into standby mode and operated it manually as well with similar results.
 

Wild Bill

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I put the TR1 into standby mode and operated it manually as well with similar results.
That is very odd and perplexing. Same shaft length as last motor?
 

Tiderunner85

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Sep 30, 2010
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Tommy
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I always thought the new T9.9 was the old T8 with maybe a few new bells and whistles to get that extra whole 1.9hp? Just throwing it in...
 

Thrasher_1

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I always thought the new T9.9 was the old T8 with maybe a few new bells and whistles to get that extra whole 1.9hp? Just throwing it in...
pretty much the same. They do come with different props, which I am wondering if that could have anything to do with it? Perhaps switching over to the T8 prop, would resolve it? It will rev a little higher than it is now tho while trolling.
 

Wild Bill

Drinking the Suzuki Kool-aid and liking it!
Aug 4, 2010
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I always thought the new T9.9 was the old T8 with maybe a few new bells and whistles to get that extra whole 1.9hp? Just throwing it in...
Up until about 2005 the 9.9 ht had the same displacement as the 15. Then they just retuned the 8 HP model and made it produce 9.9 hp. but they shared the same displacement. Now as Thrasher pointed out they only offer the 9.9 and not the 8. And it is of the smaller displacement variety. Also the 15 ht is not offered either. I believe the next size offered is the 25 ht and it is almost twice as heavy as the 9.9.
 

Johnny Dollar

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Jun 14, 2009
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Murphy
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This has nothing to do w/ any difference betwixt the two, but I think a prop guard increases the thrust and 'nozzle' effect for a little better turning
 

Thrasher_1

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first off you need to break in the motor and seat the valves, and to do that you need to run for a few hours at 3/4 to full throttle, fluctuating between those 2 every 15 minutes. Taking the new motor trolling right out of the box will never seat the valves which could account for fluctuating RPM's at trolling speeds..
I have done this a little but have I been to the "T" on the break in procedure? probably not to a T, but I have done it a little. I wonder if it is okay to simply hook the 9.9 up to the muffs (he said muffs :rofl:) and do it while in my driveway?
 
W

woodrow246

Ted, for sure on the break in..Thrasher: Do the run in under load! Dump her in and run it like BV mentioned. Run it more on the hard side for a while..
 

Clockwork

I've posted enough I should edit this section
Feb 16, 2011
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if your kicker can turn farther than your steering system can steer it then adjust it tighter to port. not familiar with the tr1 but if it goes lock to lock before the kicker swivel is maxed then you can adjust it to favor port because it takes alot more steering to turn to port if the motor is located at port. just a thought.

the rpm fluctuation sounds like an issue though. sounds alot like my motor did with a dirty carb. the fuel passages are so tiny i cant see how they wouldnt get obstructed even for a new motor.
 
Jun 26, 2009
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Bill
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pretty much the same. They do come with different props, which I am wondering if that could have anything to do with it? Perhaps switching over to the T8 prop, would resolve it? It will rev a little higher than it is now tho while trolling.

Corey, that isn't a bad thing. Actually better on the motor.
 

WaveDancer

Fishing The Pacific Ocean & Puget Sound Since 1969
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This has nothing to do w/ any difference betwixt the two, but I think a prop guard increases the thrust and 'nozzle' effect for a little better turning
It does, even more so in reverse.

WD.
 

Thrasher_1

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Update, still hate this fucking 9.9.

One thing I noticed, but can't understand how it would make a difference is, this new 9.9 is a 25" shaft and my T8 was a 20". I can't imagine that a longer shaft would make turning more difficult. If anything, wouldn't a longer shaft make it easier?

Another thought was that the 9.9 prop is the source of the problem. The 9.9 prop is larger than the previous T8. One thing I do know for see is that tryin to manually steer with the tiller is pretty damn hard compared to my T8. There is quite a bit of torque on the 9.9. Coincidentally, today while out, the TR1 cylinder bracket snapped today while trolling. The welded pin on the front of the bracket that holds the end of the cylinder sheared off. What the hell???

So far, this 9.9 was the shittiest upgrade to date.
 

Barracuda1

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I used to have a 4 stroke Evenrude kicker turned the boat really good. Then I replaced with 9.9 Yamaha same extra long foot now it won't turn unless the main is all the way out of water.
This is true on my boat as well, specifically if in a strong current or winds. Try pulling the main out of the water that's what works for me. BTW any luck?
 

Thrasher_1

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While using my t8 I never had to pull the main and the torque wasn't remotely close to what this 9.9 is.
 

Barracuda1

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Mine is mounted on the stbrd side and has trouble turning port unless the main is up or the current is slack. Oh and I do have a prop guard installed..
 

Thrasher_1

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Mine is mounted on the stbrd side and has trouble turning port unless the main is up or the current is slack. Oh and I do have a prop guard installed..
What length of shaft is your 9.9 and do you have an offshore bracket?
 

Thrasher_1

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Well, since I know that a lot of you have been losing sleep over this, I figured I'd update you. :finger:

Last night, I raised my kicker up as high as it would go, which lifted me roughly 3", bringing it back closer to the length of the original 20" shaft on the T8.

I then took it to the lake and tried it out and surprisingly enough, the boat steered impressively better. All kicker logic says that the longer shaft in the water should operate better, but for some reason it doesn't.

Now you can all sleep well.....
 

blackvelvet

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Jun 19, 2010
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Well, since I know that a lot of you have been losing sleep over this, I figured I'd update you. :finger:

Last night, I raised my kicker up as high as it would go, which lifted me roughly 3", bringing it back closer to the length of the original 20" shaft on the T8.

I then took it to the lake and tried it out and surprisingly enough, the boat steered impressively better. All kicker logic says that the longer shaft in the water should operate better, but for some reason it doesn't.

Now you can all sleep well.....

Go figure, that's the best news you coulda hoped for..........now go kill some fish while I catch up on my sleep:finger:
 

Salmon Addict

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Feb 5, 2011
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Area 7 San Juans
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Matt
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Go figure, that's the best news you coulda hoped for..........now go kill some fish while I catch up on my sleep:finger:
Well, since I know that a lot of you have been losing sleep over this, I figured I'd update you. :finger:

Last night, I raised my kicker up as high as it would go, which lifted me roughly 3", bringing it back closer to the length of the original 20" shaft on the T8.

I then took it to the lake and tried it out and surprisingly enough, the boat steered impressively better. All kicker logic says that the longer shaft in the water should operate better, but for some reason it doesn't.

Now you can all sleep well.....
Glad you figured it out! Now I think I'll raise mine up a bit at one time with a different kicker it steered great but that was when I had a different kicker. When I made the switch I did drop the kicker about 3" "thought" that would you make it even better but sounds like we were wrong.