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Author Topic:   SUPER SPORT 13 40-HP Planing Problems

fpelton posted 04-11-2007 12:35 PM ET (US)
I need some help. I have a 1987 13 SS Limited with a 2003 Yamaha [40-HP] four-stroke. There is no stingray or dolphin on the motor. I bought the boat over the winter and have been trying to get it to run to optimum performance. With one person, it gets up pretty well and does about 30-MPH. With three people and 9 gallons of gas, it doesn't want to get up on a plane.
Even if it doesn't want to get on a plan, should the RPM be up? When she is working to a plan, should the motor be around 4,000-RPM? When she is trying to get up, it is almost as if it just doesn't have good low range power. Once on a plane, she moves right along at 5,500-RPM.
I rebuilt the carbs a few months ago and changed the plugs. I brought it into the shop and they did a link and sync on the carbs with vacuum guage. They said they ran it in the water and it ran great (however, it was probably with only one person).
Should I next get a dolphin/stingray?
Am I expecting too much out of this motor?
Is there something else that I should be checking?
With what I read about a 13 footer with a 40-HP, I feel like I am just not running the way I could be.
Looking for advice,
Bob
blkmtrfan posted 04-11-2007 01:32 PM ET (US)
What is the pitch of your prop and the gear ratio of the lower unit?
Have you weighed you hull?
The Judge posted 04-11-2007 01:33 PM ET (US)
no....13's do not like to go with that much weight, they are only 13'. What is your max rpm with 1 person? Are you trimmed in all the way when you try and plane? With 3 people and 1 person up front it should plane pretty easily. If not either your prop is too big or you have other problems.
reely mine posted 04-11-2007 03:26 PM ET (US)
thats bull my 13 with 3 people 2 dogs and 2 coolers planes out no problem and i have a new merc 40 4-stroke. all i do is trim the moter down
reely mine posted 04-11-2007 03:28 PM ET (US)
with 14 gallons of gas . but still it takes a little longer to get on plane
blkmtrfan posted 04-11-2007 04:21 PM ET (US)
We have a 1969 Merc 35 hp on our 13' and I got it to plane with the following on board:
Myself,
My Wife,
My 16 Year old Daughter,
A friend of hers,
My 12 year old son,
His Cousin,
My 7 year old daughter,
A battery, and
Two steel gas cans with approximately 10 gallond of fuel
A very conservative estimate of 850 lbs
No Dole Fin or anything else funny, just put the teenagers up on the bow, everyone else was sitting in a thwart
yes my hull is dry, which is why I asked how much the hull weighs
PeteB88 posted 04-11-2007 05:34 PM ET (US)
Trim down - bow should go down WOT.
jimh posted 04-12-2007 08:20 AM ET (US)
Boat performance is related to engine horsepower and weight. As you add weight performance declines. On a small boat like a 13-foot Boston Whaler, going from one person to three people on board makes a significant increase in the total weight. This will have a significant decrease in performance.
If your boat struggles to get on plane with three people, consider going to a propeller with lower pitch.
Four-stroke engines are not known for having much power at low engine speed. The difficulty you report in getting on plane may be an artifact of your four-stroke engine's lack of torque at low engine speeds.
fpelton posted 04-16-2007 11:19 AM ET (US)
Thanks for the replys.
Over the winter, I brought the prop to a prop shop and asked them to knock it down a few degrees. I just checked the prop and I noticed that they stamped my name on it and "P15". I am assuming that means the pitch is 15. I can't imagine that it was a 17 pitch.
I am wondering if that is still too much pitch for what I am trying to accomplish?
What pitch/size prop are typical 40 4 Stroke Yamis using? I do think that I carry a fairly heavy load.
Bob
The Judge posted 04-16-2007 04:56 PM ET (US)
In order to match a prop we need to know what rpm she runs WOT with just you and what is your redline.
Fountain00 posted 04-16-2007 05:55 PM ET (US)

My father has a '87 13 SS with a 40 Evinrude with power trim. Out of the hole it planes faster than any other boat I've been in. Granted, it's with only 1 or 2 people max plus 2 tanks and gear. How much does the four stroke weigh?
This boat is very weight and trim sensitive with very little trim range. Too much and it porpoises but in the right spot it runs great. I think this boat is very sensitive to weight. We put the two tanks and gear in front of the middle seat. If put in the very back (behind the bench seat with the back) it does handle differently. Providing that you're pitched correctly try shifting weight and people and it may make a difference. Four strokes tend to weigh a bit more than 2 strokes but I'm not sure about your situation. I called Whaler about puting a 75 four stroke on my 15 Dauntless which weighs about 190 pounds more than my 60 2 stroke. They said "don't even try it". I figured that it was too much but thought maybe Whaler tried out that configuration.
fpelton posted 04-17-2007 08:00 AM ET (US)
Redline is about 6800. With just me, WOT is about 5800.
Royboy posted 04-17-2007 08:27 AM ET (US)
Some dealers have a prop try-out program, if you agree to purchase a prop from them. I did this with my 13 and it made all the difference in hole shot. I could have bought the prop a little cheaper elsewhere, but the experience was well worth the slight premium.
Roy

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Author	Topic: SUPER SPORT 13 40-HP Planing Problems
fpelton	posted 04-11-2007 12:35 PM ET (US) I need some help. I have a 1987 13 SS Limited with a 2003 Yamaha [40-HP] four-stroke. There is no stingray or dolphin on the motor. I bought the boat over the winter and have been trying to get it to run to optimum performance. With one person, it gets up pretty well and does about 30-MPH. With three people and 9 gallons of gas, it doesn't want to get up on a plane. Even if it doesn't want to get on a plan, should the RPM be up? When she is working to a plan, should the motor be around 4,000-RPM? When she is trying to get up, it is almost as if it just doesn't have good low range power. Once on a plane, she moves right along at 5,500-RPM. I rebuilt the carbs a few months ago and changed the plugs. I brought it into the shop and they did a link and sync on the carbs with vacuum guage. They said they ran it in the water and it ran great (however, it was probably with only one person). Should I next get a dolphin/stingray? Am I expecting too much out of this motor? Is there something else that I should be checking? With what I read about a 13 footer with a 40-HP, I feel like I am just not running the way I could be. Looking for advice, Bob
blkmtrfan	posted 04-11-2007 01:32 PM ET (US) What is the pitch of your prop and the gear ratio of the lower unit? Have you weighed you hull?
The Judge	posted 04-11-2007 01:33 PM ET (US) no....13's do not like to go with that much weight, they are only 13'. What is your max rpm with 1 person? Are you trimmed in all the way when you try and plane? With 3 people and 1 person up front it should plane pretty easily. If not either your prop is too big or you have other problems.
reely mine	posted 04-11-2007 03:26 PM ET (US) thats bull my 13 with 3 people 2 dogs and 2 coolers planes out no problem and i have a new merc 40 4-stroke. all i do is trim the moter down
reely mine	posted 04-11-2007 03:28 PM ET (US) with 14 gallons of gas . but still it takes a little longer to get on plane
blkmtrfan	posted 04-11-2007 04:21 PM ET (US) We have a 1969 Merc 35 hp on our 13' and I got it to plane with the following on board: Myself, My Wife, My 16 Year old Daughter, A friend of hers, My 12 year old son, His Cousin, My 7 year old daughter, A battery, and Two steel gas cans with approximately 10 gallond of fuel A very conservative estimate of 850 lbs No Dole Fin or anything else funny, just put the teenagers up on the bow, everyone else was sitting in a thwart yes my hull is dry, which is why I asked how much the hull weighs
PeteB88	posted 04-11-2007 05:34 PM ET (US) Trim down - bow should go down WOT.
jimh	posted 04-12-2007 08:20 AM ET (US) Boat performance is related to engine horsepower and weight. As you add weight performance declines. On a small boat like a 13-foot Boston Whaler, going from one person to three people on board makes a significant increase in the total weight. This will have a significant decrease in performance. If your boat struggles to get on plane with three people, consider going to a propeller with lower pitch. Four-stroke engines are not known for having much power at low engine speed. The difficulty you report in getting on plane may be an artifact of your four-stroke engine's lack of torque at low engine speeds.
fpelton	posted 04-16-2007 11:19 AM ET (US) Thanks for the replys. Over the winter, I brought the prop to a prop shop and asked them to knock it down a few degrees. I just checked the prop and I noticed that they stamped my name on it and "P15". I am assuming that means the pitch is 15. I can't imagine that it was a 17 pitch. I am wondering if that is still too much pitch for what I am trying to accomplish? What pitch/size prop are typical 40 4 Stroke Yamis using? I do think that I carry a fairly heavy load. Bob
The Judge	posted 04-16-2007 04:56 PM ET (US) In order to match a prop we need to know what rpm she runs WOT with just you and what is your redline.
Fountain00	posted 04-16-2007 05:55 PM ET (US) My father has a '87 13 SS with a 40 Evinrude with power trim. Out of the hole it planes faster than any other boat I've been in. Granted, it's with only 1 or 2 people max plus 2 tanks and gear. How much does the four stroke weigh? This boat is very weight and trim sensitive with very little trim range. Too much and it porpoises but in the right spot it runs great. I think this boat is very sensitive to weight. We put the two tanks and gear in front of the middle seat. If put in the very back (behind the bench seat with the back) it does handle differently. Providing that you're pitched correctly try shifting weight and people and it may make a difference. Four strokes tend to weigh a bit more than 2 strokes but I'm not sure about your situation. I called Whaler about puting a 75 four stroke on my 15 Dauntless which weighs about 190 pounds more than my 60 2 stroke. They said "don't even try it". I figured that it was too much but thought maybe Whaler tried out that configuration.
fpelton	posted 04-17-2007 08:00 AM ET (US) Redline is about 6800. With just me, WOT is about 5800.
Royboy	posted 04-17-2007 08:27 AM ET (US) Some dealers have a prop try-out program, if you agree to purchase a prop from them. I did this with my 13 and it made all the difference in hole shot. I could have bought the prop a little cheaper elsewhere, but the experience was well worth the slight premium. Roy