Suzuki DF4-6 question

[jswindel]

I am looking for a 4-6 HP outboard for my boat. I noticed that the specifications for the Suzuki DF4, DF5 and DF6 are identical except for the power output and the rapidly increasing price. Presuming these are all the same basic engine, what is the difference that gives the extra power? The obvious next question is, could you buy a DF4 and alter it to get 6HP out of it?

 

[VicS]

Quite common to find a range of outboards using the same or similar engine lump.

Carbs may be different, porting may be different, the lowest power may even be achieved with a restrictor between carb and engine. There's one , I forget which, that simply has a stop that prevents the throttle opening fully.

Sometimes quite simple to uprate (eg if only a restrictor plate has to be removed or a throttle stop removed) Other times no so simple. I have a 6hp Evinrude which although the same basic engine cannot easily be uprated to 8 hp.(the porting is different so the engine blocks are different) The similar 5hp can however be uprated to 6hp.

Notice that the Suzukis have different max revs. so same engine going faster delivers more power. In addition to carbs, porting etc there may be ignition differences ... I dont know about that ... that allow the higher speeds.

If you want a 6hp buy a 6hp dont bank on being able to uprate a 4 hp at leat not without finding out what would be involved.

 

[Manuel]

That engine has issues. Look around at others.

 

[Chris_Robb]

That engine has issues. Look around at others.

I am not sure your knowledge is still relevant as I beleive the newer models have sorted the original problems which led to much bad words about them here.

I have had one now for the summer, 2.5HP) and I must say I cannot fault it. The water cooling is positively niagra-like now. It is also much easier to start than the previous 2 stroke I had.

 

[JIM_TEAL]

Upgrade to 6hp

I have one of these. reliable so far after 2 seasons.
4hp becomes 6 by turning the throttle stop around on top of carb; = higher revs = extra power. A knowledgeable o/b mechanic did it for me. Unfortunately I cannot remember the original layout but I'll try and remember to take a photo of the arrangement next time I get to the boat and post.
Jim J

 

[JIM_TEAL]

Throttle stop

Here is the reversed throttle stop done by the mechanic to give 6hp from the 4 hp badged unit.

Jim

 

[nathanlee]

That engine has issues. Look around at others.

Mine ceased after two days. Got it repaired, and it's been fine since. I would look for a twin though.

 

[jswindel]

Do they really charge several hundred pounds extra just for turning a throttle stop over?

 

[vancrash]

tnx a lot

 

[rmartika]

Thanks jim_teal so much, I`ll try to do this and tell later succees.

 

[fxhedge]

Did your mod work. was advised by the dealer that mods were also required to the carb pins as well as throttle stop

 

[toyo321]

You need the carb internals swapped also.

DF4= main jet is a 70 DF6= main jet is a 78
DF4= pilot jet is a 35 DF6= pilot jet is a 38
DF4= Main nozzle part number 13236-91j30 DF6= 13236-91j20

 

[toyo321]

I am looking for a 4-6 HP outboard for my boat. I noticed that the specifications for the Suzuki DF4, DF5 and DF6 are identical except for the power output and the rapidly increasing price. Presuming these are all the same basic engine, what is the difference that gives the extra power? The obvious next question is, could you buy a DF4 and alter it to get 6HP out of it?

You will have to buy the main and pilot jets also. In cluding the meter main jet. With these three parts you should be there. The Thermostat is questionable.

 

[fxhedge]

What about the Intake Manifold

I'm looking at the parts list from Suzuki and see that the intake manifold is also different. The list keeps getting longer. Now we have the throttle stop, carb jets and intake manifold.

Has anyone actually converted a DF4 or 5 to a DF6 and knows everything that needs replacing?

 

[Manuel]

Has anyone actually converted a DF4 or 5 to a DF6 and knows everything that needs replacing?

Gearbox and propellor (pitch)? Is the crankshaft the same (compression)? Spark plug? Are the valves the same? (6hp is 50% uplift on 4hp). Sounds like a fun project starting out with a completely defunct DF4 (not hard to find).