# Yamaha F 9.9 vs T9.9 or Mercury 9.9 vs 9.9 Big Foot



## Gotem (Jun 24, 2014)

As I look for a new 9.9 to get next year, I've looked at all the major brands in my area. I've eleminated Nissan/Tohatsu, Suzuki, and Evinrude because there are no dealers that are near by (two local Evinrude dealers refuse to carry the 9.9 made by Tohatsu). Ok that leaves me with a lot of Mercury and Yamaha dealers where I live.

I have a boat that has been highly modified and the 1974 Evinrude 9.9 can just get me up to plane but moving weight around in the boat effects performance. So with weight as an issue is the Yamaha High Thrust or the Mercury Big Foot worth the extra money and weight. Would there be an increase in top end speed? I know a 15 or 25 horse would make my concerns mute, but I fish this boat on horsepower restricted lakes.

I'm not really concerned with brand loyalty, but the actual differences within the Yamaha outboards and within the Mercury outboards.


----------



## turbotodd (Jun 25, 2014)

I know the Yamaha motors specifically.

The T9.9 is a sailboat motor, or made specifically for displacement type hulls. HEAVY loads, slow. It's got a 2.92 lower unit. The regular 9.9 is a 2.08 lower unit-really would be a better all-around motor for what you're doing. Hopefully the Merc guys will chime in for the bigfoot questions.


----------



## TNtroller (Jun 26, 2014)

The Nissan/Tohatsu/Suzuki are basically the same as the Merc except for color and stickers, but the Merc dealer may not see that way.


----------



## Snowshoe (Jun 26, 2014)

Every 30 HP Mercury and smaller that I've seen is made by Tohatsu. Same motor, just different color and stickers.


----------



## turbotodd (Jun 27, 2014)

I also failed to mention that the T9.9 is only available in 20" shaft and 25" shaft. Long and X-long. So if you have a 15 or 16" transom, the 20" will be 4 or 5" too long. As I said, it's more of a sail boat motor or kicker and nothing more. It is slow. But it makes a lot of thrust to move a displacement style hull that will never plane. 

A F9.9 would be a better bet, and quite a bit faster than an earlier model 9.9 of most brands. Reason being, the horsepower rating changed. At one point the horsepower was rated at the flywheel and it was changed to be rated at the propshaft, IIRC. So did the technology. Now we have better lower units that cut through the water better, better props, etc. Just sold and prepared a F9.9 today for a customer-I was running it in the test tank while the guy was standing there talking to me and he asked me if he could see it run before he loaded it.


----------



## stevesecotec02 (Jun 27, 2014)

The big foot is designed for heavy loads and is slower than a regular 9.9. If you live where there are 10hp restrictions your best bet is to get a 2 stroke 9.9 and swap the carb to make it a 15.


----------



## turbotodd (Jun 28, 2014)

[url=https://www.tinboats.net/forum/viewtopic.php?p=357307#p357307 said:


> stevesecotec02 » Yesterday, 03:32[/url]"]The big foot is designed for heavy loads and is slower than a regular 9.9. If you live where there are 10hp restrictions your best bet is to get a 2 stroke 9.9 and swap the carb to make it a 15.




I looked up the part numbers on a 2006 9.9 carb and it's the same carb as a 15. Had to replace a carb on a guy's 9.9 recently and thought the same thing...might as well put a 15hp carb on it-but they are the same part number for the 9.9 and 15. 63V-14301-10-00, fits 04-06 9.9 and 15. 

63V-14301-00-00 fits 96 through 2003 15 and 9.9 both. 

Where the difference is in the 2 motors is beyond me. I haven't researched it. Lot of the parts interchange between the 2. I was for some stupid reason thinking that the reed valve assembly is different and possibly the ignition timing, but I have not researched it.

That said, if one was to buy a 15 hp carb and put it on an otherwise stock 9.9, you'd still have a 9.9 and your wallet would be $220 lighter.


----------



## stevesecotec02 (Jun 29, 2014)

It depends on year of motor. Some are just carb while others are more involved and include reeds and even the exhaust ports.


----------



## Pop (Nov 17, 2014)

Don't want to hi jack this thread, but I am having a similar problem and decision to make. I am now really confused. (Not mechanically inclined). I am looking to purchase a Tracker Grizzly with side console. I also fish lakes with a 10hp limit. Trying to decide on the 14ft model or the 16ft model. Only considering the 14ft thinking the 9.9 would push better. Thought the Big Foot would do a better job, but; from what I am reading is maybe the regular 9.9 would be better. What is the answer? 14' has a 17.5 transom. The 16' is 21' transom. Thanks, Pop


----------



## turbotodd (Nov 17, 2014)

As said, the only thing the big foot's are good for is pushing a HEAVY displacement style hull, like a sail boat kicker, or a kicker on a bay style boat or the like. All others should be using a regular foot a.k.a non bigfoot.

Go with the 14 unless you need the extra real estate, but be aware that some states have more regulations with relationship to 16' and longer boats than shorter than 16'. Like here, if over 16' you must carry a throwable PFD, must have a horn, must carry a fire extinguisher, etc. If the boat were shorter than 15' (as defined by the laws here, 15'6" or shorter), then you don't have to carry those items. And they can take up space which can be an issue. One way around that stuff is to get as wide a boat as you can get. I had a guy bring in a 1460 a while back for me to do some work on the motor and I could not believe the amount of space inside! I don't know who made the boat, but I sure did like it. 1448 is a common size and a good combination of width and length.


----------



## Gotem (Nov 22, 2014)

I ended up spending some money to get the issue fixed with my mid-70's 9.9. It turned out to be something electrical and the Evinrude replacement part which they originally used was faulty. They had to use an after-market part. I've decided to do what I need to to keep my "9.9" running since it has a 15 hp carb. The reason being I think a new 9.9 may smoke my 9.9 in its original configuration, but it would still not beat my 9.9 with the 15 hp carb adjustment. 

The difference with the 15 hp carb is quite noticeable. The original 9.9 setup would struggle greatly to get the boat on to plane. The 15 hp carb does it without a problem. As for speed it only increased it from 9-11 to 12-14 mph. Weight distribution is no longer an issue. (For the record a 6 hp Johnson from the same year would plow the boat forward at about 6 mph).

As a much as I was thinking of a new 9.9, I will not do it until my old one breaks beyond repair. The old 9.9 is also about 20 lb lighter than the new 4-stroke. The only way to tell that it is really a 15 hp is to take the carb apart and nobody is going to do it since the boat is not going that fast. Once again a 25 hp would fix everything, but I fish horsepower restricted lakes.


----------



## Pappy (Nov 24, 2014)

stevesecotec02 said:


> It depends on year of motor. Some are just carb while others are more involved and include reeds and even the exhaust ports.



On the Johnson/Evinrude product the exhaust ports never were different on that family of engines, from 1974 until the end of the two stroke production run.
On the 1974 engine you had to change the carburetor (9.9 to 15hp) for the biggest change then the exhaust pipe to the exhaust tuner. Those were the two main changes. The third one makes a small difference and that is the reed block shim. The exhaust pipe/tuner change went away with the last version of engines as did the reed shim. 

The best change for the OP here would be to modify his engine and leave the 9.9 sticker on the side of the cowling. For the heavier load leave the 9.9hp prop on the engine.


----------

