BillyBloater
regular
Reged: 09/01/2006
Posts: 344
Loc: UK
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Last year I bought a new Suzuki DF 9.9hp outboard. I noticed at the time that the 9.9hp and the 15hp models are very similar, same cubic capacity etc.
I am damn sure that the 9.9 must be a restricted version of the 15hp but I am buggered if I can see how Suzuki have done it. I had hoped that there might be a restriction in between the carb and the inlet manifold but having looked this doesn't seem to be the case.
I contacted a Suzuki dealer who passed me over to the Suzuki UK Technical Department. The Tech dept said that they 'do not recommend modifying the engine in the nature you have described'.
Not knowing how the engine is restricted is driving me mad. Can anyone shed any light or point me in the direction of someone who might be in the know and willing to share the big secret!
Cheers
Billy
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"He is not only dull himself, he is the cause of dullness in others."
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alrob
regular
Reged: 19/07/2005
Posts: 812
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not sure if its the same scenario but the 2.5 HP & 3.3hp mercs are the same engine but the gearing is different. also been told that in big outboards the jets can be altered to give more output
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misterg
regular
Reged: 31/10/2003
Posts: 1443
Loc: N. Wales
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Quote:
not sure if its the same scenario but the 2.5 HP & 3.3hp mercs are the same engine but the gearing is different....
2.5 & 3.3 Mariners are the same engine, but the 2.5 is restricted by the throttle slide not opening fully - it is physically to long to do so. (I suspect this applies to Mercuries, etc. too.) Number of gear teeth is different because the 3.3 has a F-N gearshift, but the 2.5 doesn't. Overall gear ratio is nearly the same though (from memory).
May be worth checking the Suzuki for the same thing on the throttle slide. Is the part number of the carb for both engines the same? Is there a 'changeable' venturi in the carb? I suppose there could possibly be a restrictor in the exhaust or air 'filter'?
Andy
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spannerman
regular
Reged: 30/11/2002
Posts: 1042
Loc: Stavanger, Norway
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If I remember correctly ypu have to change the carb on Suzukis and maybe adjust the stop on the reed valve which determines how much they open.
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jfm
regular
Reged: 16/05/2001
Posts: 7487
Loc: London/Antibes
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I dont know that particular model but it's normally done by restricting the diameter of the carb jet(s) to restrict the fuel flow. It is not normally done by restricting the throttle opening (which restricts the air flow, not the fuel flow). So, just taking the carb to bits and fitting the 15hp jets should do it. Quite simple job if you are ok with carbs. or your local motorbike shop could do it
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MVP
regular
Reged: 05/09/2007
Posts: 64
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Messing about with modern engines is going to be a high risk game and will invalidate any warantee.
If you wanted a 15hp engine why didn't you buy one?
MVP
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itsonlymoney
regular
Reged: 21/06/2003
Posts: 4381
Loc: UK
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Quote:
2.5 & 3.3 Mariners are the same engine, but the 2.5 is restricted by the throttle slide not opening fully - it is physically to long to do so. (I suspect this applies to Mercuries, etc. too.)
So how would one get round this and make the slide open fully ?
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jfm
regular
Reged: 16/05/2001
Posts: 7487
Loc: London/Antibes
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Oh come on, be more adventurous! Changing a few carb jets is a piece of cake. And why worry about warranty? The thing only cost a thousand quid anyway so what's the worst that can happen?
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BillyBloater
regular
Reged: 09/01/2006
Posts: 344
Loc: UK
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Quote:
Messing about with modern engines is going to be a high risk game and will invalidate any warantee.
If you wanted a 15hp engine why didn't you buy one?
The 9.9 was on special offer. I couldn't muster enough points with SWMBO to get hold of the extra £200 for the 15hp
The idea about the throttle cable / slide being limited is well worth looking at.
I have looked at the schematic for the 9.9 and the 15, both share the same drawing. Any ideas:
MVP
REF# PART #REQ YOUR PRICE
1-1 CARBURETOR ASSY
13200-94J20 1 $263.09
1-2 CARBURETOR ASSY
13200-94J30 1 $290.78
1-3 CARBURETOR ASSY
13200-94J60 1 $263.09
2-1 NOZZLE,MAIN
13236-94J10 1 $13.41
2-2 NOZZLE,MAIN
13236-94J00 1 $13.41
3-1 .JET, MAIN (70)
09491-70017 1 $7.94
3-2 JET,MAIN 115
09491-23029 1 $7.07
4-1 .JET, PILOT (38)
09492-38009 1 $8.21
4-2 JET,PILOT 40
09492-40029 1 $7.07
5 CAP,RUBBER
13239-94J00 1 $3.86
6 FLOAT
13250-94J00 1 $19.24
7 VALVE COMP,FLOA
13370-94J00 1 $12.60
8 SCREW
13247-94J00 4 $4.80
9 .CLIP
13375-26E00 1 $3.09
10 PIN,ARM
13254-94J00 1 $1.68
11 SCREW
13802-94J00 1 $1.76
12 SCREW,STOP
13534-94J00 1 $4.15
13 SPRING
13268-94J00 1 $2.34
14 GASKET,FLOAT CH
13251-94J00 1 $6.12
15-1 CHAMBER,FLOAT
13245-94J00 1 $34.99
15-2 CHAMBER,FLOAT
13245-94J10 1 $34.99
15-3 CHAMBER,FLOAT
13245-94J20 1 $34.99
16 SCREW,DRAIN
13279-94J00 1 $2.85
17 O RING
13523-94J00 1 $2.34
18 U RING
13345-94J00 1 $3.86
19-1 COVER
13346-94J00 1 $11.47
19-2 COVER
13346-94J10 1 $10.78
19-3 COVER
13346-94J20 1 $11.47
20 SCREW
13247-94J00 4 $4.80
21 HOLDER,CABLE
13361-94J00 1 $7.68
22 GUIDE,CABLE
13362-94J00 1 $6.90
23 CAP,CABLE SEALI
13363-94J00 1 $6.12
24 VALVE,STARTER
13364-94J00 1 $8.46
25 SPRING
13365-94J00 1 $2.34
26 .O RING
13295-14G00 (replaces 13366-94J00) 1 $1.81
27 PIPE
13684-94J00 1 $5.22
28 .CLIP
09401-05402 1 $0.68
29 .PLATE
13428-06F30 1 $2.90
30 SCREW
13367-94J00 1 $2.34
31 STARTER ASSY
13368-94J00 1 $114.73
32 CLIP
13494-94J00 1 $3.47
33 CAP,RUBBER
13495-94J00 1 $5.22
34 PLUNGER
13493-94J00 1 $11.44
35 SPRING
13441-94J00 1 $2.34
36 BOLT
09103-06276 2 $1.85
37 GASKET,CARBURET
13125-94J00 1 $2.47
38 INSULATOR,CARBU
13124-94J00 1 $5.77
39 GASKET,INSULATO
13127-94J00 1 $2.63
40 KNOB ASSY,START
13640-94J00 1 $15.29
41 PROTECTOR,START
18498-94J00 1 $2.05
42 CLAMP
09403-12318 1 $1.51
43 PLUG,STARTER KN
59252-94J00 1 $4.24
Cheers
Billy
--------------------
"He is not only dull himself, he is the cause of dullness in others."
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jfm
regular
Reged: 16/05/2001
Posts: 7487
Loc: London/Antibes
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The HP restriction is VERY unlikely to be done by restricting the airflow (throttle). I repeat, it is done by the carb jet sizing. So just change the jets. Parts 2, 3, 4. Quite cheap, less than a £fiver per item. Note, each one of these 3 parts is listed twice, with a different dimension code. One set will be for the 9.9, t'other for the 15hp. Which kinda proves my point
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