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Author Topic:   Trolling Motor Recommendation, 9.9 or 15 hp

JOHN W MAYO posted 06-24-2003 09:29 AM ET (US)
I am considering buying a trolling motor, also to be used as a back up in the sound and ocean in NC.
Boat|
Boston Whaler 19 Revenge
150 merc 1500
weight approx 2500 lbs with everthing
What shaft length 20 or 25?
What hp? 9.9 or 15 hp?
What speed could I expect out of both engines?
Considering a used Mariner 1991 9.9 20in, used for $595 or a new Yamaha, for around $1900
Recommendation on 2 stroke or 4 stroke?
Thanks in advance for your input.
Tom2697 posted 06-24-2003 10:31 AM ET (US)
John,
I am in the same market as you and I believe with the same boat ('89 Outrage 18). I was looking at various motors to get me in should my main motor die. I have found some interesting stuff...
A 20" shaft is the minimum as I've had to use a friend's motor with a 15" shaft to move my boat when my old engine died. The 15" shaft worked but the prop would ventilate if I ran the motor at more than 3/4 throttle. Here is the interesting part: the motor that I used was a 3.3 hp Merc 2-stroke. My boat was moving along (in a channel but directly against the wind and an incoming tide moving at about 3 knots) at around 4 knots. I was surprised to learn that his blowboat motor would move my boat as it did and in such conditions.
So, I believe that you would be fine with the 9.9 Mariner. The price for it also sounds better than for the Yamaha. As for the 2-stroke vs 4-stroke issue, I don't want to start another battle on this topic but consider what you are currently running on your boat. If you have pre-mixed gas in your main tank, go with the 2-stroke. If you have oil fed by the motor or a 4-stroke on your boat, go with a four stroke. You can always run a spur line off the main line to feed your kicker, assuming the cause of needing the kicker is not contaminated fuel....(My opinion only!)
Tom
acseatsri posted 06-24-2003 11:33 AM ET (US)
I've had both an 8 horse and a 10 horse on my 18OR- there is no discernable difference between the 2- basically it's not enough to plane, so you're limited by that parameter. I had an 8 horse 20" shaft on the port side- monster list to port when underway due to prop torque. I came across a 10 horse short shaft which I mounted on a bracket on the starboard side this year, a marked improvement in the list. Whatever you get, I'd definitely opt to mount it on the starboard side- bracket mounting may be necessary if you have cable steering.
jimp posted 06-24-2003 04:48 PM ET (US)
John -
I'm running a 1990 Yamaha 9.9 4-stroke hi-thrust on my 1990 Revenge 22 W/T. Mounted on the transom (Cetacea 44). Top speed is about 5.6 kts.
JimP
gnr posted 06-24-2003 04:59 PM ET (US)
If you are going to put many hours on it trolling I would highly recommend a fourstroke. My wife will actually go fishing with me once in a while now that she doesn't have to breath two-stroke smoke all night.
FYI my little Honda 5hp pushes my 17 Guardian at 5.8 mph (gps) into a light wind. I trolled over thirty hours in a fishing derby weekend before last and didn't finish a three gallon tank.
Kingsteven18 posted 06-24-2003 06:20 PM ET (US)
Most 15's are 'tweaked' 9.9's. So if they offered a 15 in the same series, you could probably modify the 9.9 to put out the 15hp.
Steve Leone posted 06-25-2003 12:57 AM ET (US)
True. Alot of 15hp outboards are just stressed out 9.9`s. The Honda is a good example. From 1979 thru 1989 the 7.5 was produced alongside the 10hp. The ONLY difference between the two was the camshaft. The 7.5 would, in my opinion, last longer than the 10hp. The same goes for the Honda 9.9 and 15hp. Allthough the 15hp in the latter years has a different sized jet in the carburetor plus the larger cam. An interesting point: Honda, (and many outboards for that matter) discarded the adjustable air/fuel mixture screw for the slow speed circuit due to emission standards set by the feds. If you purchase a new Honda for example, it is impossible to negotiate the slow speed air/fuel mix. This creates a problem after the engine has some time on it as most rough idle conditions were smoothed out with the mixture screw. Now you have go in and adjust the valves more frequently and in some cases replace the cam. Some outboards have power porting or cut outs in the piston to increase the hp, even though they have the same cylinder bore size. Racing engines are a good example of this manuever. Sometimes you can go too far though as Suzuki did with some of thier earlier model two-strokes (30hp for example). They took it to the edge and were extremely fine line machines. The trouble was when the fuel changed (more alchohol) they would not run right no matter what you did. Steve
JOHN W MAYO posted 06-27-2003 09:32 PM ET (US)
Thanks to everyone for the great information. Now I have a better understanding of what the kicker motors will do with speed, current, hp, etc..
Some very good points of view. I can lean from your experience with the smaller engines.

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Author	Topic: Trolling Motor Recommendation, 9.9 or 15 hp
JOHN W MAYO	posted 06-24-2003 09:29 AM ET (US) I am considering buying a trolling motor, also to be used as a back up in the sound and ocean in NC. Boat\| Boston Whaler 19 Revenge 150 merc 1500 weight approx 2500 lbs with everthing What shaft length 20 or 25? What hp? 9.9 or 15 hp? What speed could I expect out of both engines? Considering a used Mariner 1991 9.9 20in, used for $595 or a new Yamaha, for around $1900 Recommendation on 2 stroke or 4 stroke? Thanks in advance for your input.
Tom2697	posted 06-24-2003 10:31 AM ET (US) John, I am in the same market as you and I believe with the same boat ('89 Outrage 18). I was looking at various motors to get me in should my main motor die. I have found some interesting stuff... A 20" shaft is the minimum as I've had to use a friend's motor with a 15" shaft to move my boat when my old engine died. The 15" shaft worked but the prop would ventilate if I ran the motor at more than 3/4 throttle. Here is the interesting part: the motor that I used was a 3.3 hp Merc 2-stroke. My boat was moving along (in a channel but directly against the wind and an incoming tide moving at about 3 knots) at around 4 knots. I was surprised to learn that his blowboat motor would move my boat as it did and in such conditions. So, I believe that you would be fine with the 9.9 Mariner. The price for it also sounds better than for the Yamaha. As for the 2-stroke vs 4-stroke issue, I don't want to start another battle on this topic but consider what you are currently running on your boat. If you have pre-mixed gas in your main tank, go with the 2-stroke. If you have oil fed by the motor or a 4-stroke on your boat, go with a four stroke. You can always run a spur line off the main line to feed your kicker, assuming the cause of needing the kicker is not contaminated fuel....(My opinion only!) Tom
acseatsri	posted 06-24-2003 11:33 AM ET (US) I've had both an 8 horse and a 10 horse on my 18OR- there is no discernable difference between the 2- basically it's not enough to plane, so you're limited by that parameter. I had an 8 horse 20" shaft on the port side- monster list to port when underway due to prop torque. I came across a 10 horse short shaft which I mounted on a bracket on the starboard side this year, a marked improvement in the list. Whatever you get, I'd definitely opt to mount it on the starboard side- bracket mounting may be necessary if you have cable steering.
jimp	posted 06-24-2003 04:48 PM ET (US) John - I'm running a 1990 Yamaha 9.9 4-stroke hi-thrust on my 1990 Revenge 22 W/T. Mounted on the transom (Cetacea 44). Top speed is about 5.6 kts. JimP
gnr	posted 06-24-2003 04:59 PM ET (US) If you are going to put many hours on it trolling I would highly recommend a fourstroke. My wife will actually go fishing with me once in a while now that she doesn't have to breath two-stroke smoke all night. FYI my little Honda 5hp pushes my 17 Guardian at 5.8 mph (gps) into a light wind. I trolled over thirty hours in a fishing derby weekend before last and didn't finish a three gallon tank.
Kingsteven18	posted 06-24-2003 06:20 PM ET (US) Most 15's are 'tweaked' 9.9's. So if they offered a 15 in the same series, you could probably modify the 9.9 to put out the 15hp.
Steve Leone	posted 06-25-2003 12:57 AM ET (US) True. Alot of 15hp outboards are just stressed out 9.9`s. The Honda is a good example. From 1979 thru 1989 the 7.5 was produced alongside the 10hp. The ONLY difference between the two was the camshaft. The 7.5 would, in my opinion, last longer than the 10hp. The same goes for the Honda 9.9 and 15hp. Allthough the 15hp in the latter years has a different sized jet in the carburetor plus the larger cam. An interesting point: Honda, (and many outboards for that matter) discarded the adjustable air/fuel mixture screw for the slow speed circuit due to emission standards set by the feds. If you purchase a new Honda for example, it is impossible to negotiate the slow speed air/fuel mix. This creates a problem after the engine has some time on it as most rough idle conditions were smoothed out with the mixture screw. Now you have go in and adjust the valves more frequently and in some cases replace the cam. Some outboards have power porting or cut outs in the piston to increase the hp, even though they have the same cylinder bore size. Racing engines are a good example of this manuever. Sometimes you can go too far though as Suzuki did with some of thier earlier model two-strokes (30hp for example). They took it to the edge and were extremely fine line machines. The trouble was when the fuel changed (more alchohol) they would not run right no matter what you did. Steve
JOHN W MAYO	posted 06-27-2003 09:32 PM ET (US) Thanks to everyone for the great information. Now I have a better understanding of what the kicker motors will do with speed, current, hp, etc.. Some very good points of view. I can lean from your experience with the smaller engines.