New outboard/low power - is the dealer telling porkies ?

affinite

affinite

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I recently bought a new 4Stroke 6hp Suzuki outboard and a new 2.7m airdeck inflatable as a tender package.
I set both up exactly as per the manuals (including using a pressure guage to get the boat pressure just right) and have been careful to observe the guidance re breaking in.

Trouble is there isnt enough power to get the ouftit on the plane with two up. (It actually struggles a bit with one up!)

The dealer has told me that the engine is tight and needs to be run in to loosen up and then it will deliver full power. He claims that some outboards can be 15% short of full power when brand new.
Is this likely to be true ?

What does the panel think ?

Bye the way I was concerned that the anti cavitation plate is a good 3-4 inches below the bottom of the transom. Raising the engine just 3/4 inch made a big difference but it is a std shaft.

Help !!

Steve (Affinite)
 
I have a Quicksilver 340 Airdeck with a 6HP Honda 4 stroke. It wasn't bought with planing in mind, but, a small modification to the throttle stop gives 33% power uplift. It now planes with me on board and tries to plane with both of us onboard. Maybe the Suzuki has a similar modification opportunity. I think the QS340 weighs in at 43kgs. I didn't notice any power difference after the running in period, but definitely noticed after bending the throttle stop.
 
Why did the dealer sell you a standard shaft engine if you need a short shaft for the tender surely he must have known what length you required? take it back as it's not the right size. As for the 15% how did he measure that?

Pete
 
My 2.7 Honwave airdeck and 5bhp Honda wouldn't plane at all.

I may as well have bought a 2.3bhp engine for all the good the 5hp version did /forums/images/graemlins/frown.gif
 
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Why did the dealer sell you a standard shaft engine if you need a short shaft for the tender surely he must have known what length you required? take it back as it's not the right size. As for the 15% how did he measure that?

Pete

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As I have always understood it, a "standard shaft" is a short shaft??? I have never seen a manufacturer offering anything but standard and long shaft.......

Regarding 4 strokes in the small sizes ie 4-5-6hp, I don't really think that they are as good at planing an inflatable tender as a 2 stroke of comparible size, what the 4 stroke has in abundance is grunt, but not snappy accelaration that a 2 stroke has, they are also heavier, which compounds the problem. I used to have a 2.3m inflatable with an inflatable floor and keel an air rib if you like, I used a 4hp Yamaha 2 stroke on that and would plane easily, I tried a friends 4 stroke Honda 5hp on it, and wouldn't get on the plane. Maybe it's because of lower revs?
 
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As I have always understood it, a "standard shaft" is a short shaft??? I have never seen a manufacturer offering anything but standard and long shaft.......

[/ QUOTE ] The terms are often confused, Mariner for example use "short" and "long shaft".

However, the way I read the post it sounds like the Suzi has the wrong shaft length, it's too long, the dealer would have known that.

Pete
 
I agree, people use the terms "short" and "standard" as meaning the same thing, though something has been twitching in the darker recesses of my mind.....wasn't there at least one manufacture that once offered three options ie "short", "standard", and "long".......Johnson maybe???

PS. I just read the original post again, and he says his cavitation plate is a good three to four inches below the transom! I read it as 3/4 inches! Doh!.......Hmmmmsounds like he might well have a long shaft?
 
I bought the Suzuki 6hp and a Zodiac 3.4m RIB at LIBS 2005 having been promised by the dealer that it would plane 'easily' two-up. It never has but will one-up. I am going to follow-up the other's suggestion of checking for a throttle stop.

By the way, I have this year cleaned the carb of mine for the first time (previously had it done, as the engine was under warranty). It was very easy to do even with the engine on the boat in the water. After the engine failed to start this Spring, I squirted some neat fuel into the air intake when it fired an ran perfectly for a few seconds. So ignition, valves, etc. were OK. It was a blocked main jet which I cleared with a bit of fuse wire.

I'll check out for a throttle stop and report back.
 
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It was a blocked main jet which I cleared with a bit of fuse wire.


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I wouldn't advise using wire to clean jets -you can scratch / modify the hole - thus causing future problems -often you are lucky and get away with it -but compressed air is the safest way to clear them - if stuck a nylon bristle (yep my toothbrush) or fishing line are much safer options.
 
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I am going to follow-up the other's suggestion of checking for a throttle stop.

I'll check out for a throttle stop and report back.

[/ QUOTE ]

Hmmm, wonder if it would make my little Suzuki 2.5 a 4 /forums/images/graemlins/grin.gif

It would probably disappear up it's own exhaust!
 
Another possibility is the wrong prop pitch if the engine is reving out (not that you get a lot of options on a small outboard). As it's a modern outboard, check that it's not got a saildrive prop.
 
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I wouldn't advise using wire to clean jets -you can scratch / modify the hole - thus causing future problems -often you are lucky and get away with it

[/ QUOTE ]I'm grateful for the warning but do you really think that tinned copper wire is going to scratch a brass jet? I clean our cooker jets with tinned copper as well and it works fine. I never use enough vigour to remove even the tin/lead coating.

Steel wire, maybe, although standard prickers have been made from stainless steel wire for donkey's years. Brass is quite hard. The hole on an outboard main jet is not so terribly critical, either, and we are not expecting an accuracy of microns. The variation between different fuels is pretty great, with the changes in composition due to ethanol so miniscule differences in the jet are surely not going to be material?

You surprise me if there is a problem, though this isn't my discipline - is there any evidence of a problem?
 
It's just one of those bits of perseved wisdom, really it's about doing it over time, thus altering the orifice in the jet, your bit of tinned copper wire just used once in a while isn't likely to cause any harm, though it might if you was to do it every week for the next ten years! /forums/images/graemlins/wink.gif
 
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[I'm grateful for the warning but do you really think that tinned copper wire is going to scratch a brass jet?

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Thank you - I'm glad you said that. I thought I was alone in thinking this was a load of old nonsense. If I ever need to enlarge a hole I tend to use an HSS drill bit rather than a bit of wire.
 
from the response of others it sounds as if 6hp is marginal to get a 2.7m boat onto the plane. Yes the power in a new engine will be slightly down because its tight but whether its 10 15 or 20 % .................

Must also be said that getting the boat onto the plane depends on the porkiness or otherwise of the crew. With me on board you would need 15hp at least!
 
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I thought that fuse wire was soft enough for that job??

[/ QUOTE ] Thats what i use , or any other bit of soft copper wire.

Toothbrush bristles are not long enough for some jets. Nylon fishing line is fine if you have it handy but not everyone does.

Just dont use ordinary wire brush bristles.
 
I weigh 13st & my XM240 will JUST plane with a 5hp if I sit forward to keep the bow down or station a small grandchild in the bow. With 2 adults there is no chance of planing.

I would guess that 6hp is pretty marginal for planing & to some extent will depend on the dinghy hull shape. Does it have any form of keel (internal wood bar or inflated keel)?
 
urban myth compounded by years of thumblethumbs re iterating the same old thing, have been fixing engines for 50 years and they used to say that 50 years ago, have used anything from a wire pulled out of a wire brush to a piece of fishing line, have never ever had a prob due to enlarged jets!
Stu
 
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