First Voyage!... a little slooow.. :-(

[ferryden]

... yup I was really surprised how fast the keel filled (expecting there to be some air needed in side panels to keel itself)! I used a 12v battery airpump to do initial fill then used double handed stirrrup pump ...but not to the measured pressure and I think this is where I blew it.

But I read someone saying that the Quicksilver valves auto shut of at max pressure...is this right? If so does this mean we can't overfill our Quicksilver tubes and therefore I don't need the new pump with gague? Hmmmnn...

By the way I have spelled 'guage' differently every time..sorry guys!

F

[Sinistre1]

That's odd. I know I typed a response last night but it is not here today. Anyways, I also thought we had protection valves but we do not, or at best they do not kick in til WAAAYYY over pressure! Lol.

[simsy]

15 hp 2 stroke on this boat should fold it in half if it's not inflated correct....
You should have plenty of power..
Is the prop in the correct range (as asked before)????
It should lift the nose out and almost flit over, unless your son is right at the bow....

It will be fine when you get it inflated and engine is prooved correct....

[ferryden]

Well I'm just back from Mallorca, where I used the boat... inflated the tubes right up to max all round (bit worried they'd then pop as it was hot out there...must take pump n gague out with me to check next time)
A bit better/more speed than last time but still never got the bloody thing to plane...grrrr!
Next thing will be to get a new prop fitted, and if no joy I'll have to be to accept expensive defeat and invest in a newer engine next year... disappointing as I was looking to skimming across the blue :-(
The manual says the Quicksilver has a max hp of 15 whereas I'd thought it was 20 (new models show 20hp).. if I do have to look for another engine, is it worth taking the chance on a 20hp (a tad overspec)? I just want the bloody thing to FLY now!

Cheers guys!
F

[Max...]

A 3.4m airdeck should go very well indeed with a 15 and should not have a 20 fitted. With just me on board my 3.4 will do 20mph with a 9.8 Tohatsu and 17mph with 2 adults and 2 small kids - something is drastically wrong with your engine power or set-up if it won't even plane with a 15! If you leave it inflated to max pressure in the med sun then you need to let some air out or risk damage.

[Fenlander]

There is something very wrong here. If you are solo (?) or two up this outfit should hop on the plane even with a below par 15hp, slightly soft boat or a tired prop.

So what pressures are you calling max and how are you judging the pressure?
What happens as you approach the transition speed (about 9mph) to plane?
Does the floor hump up in the middle, do the tubes start to fold/flex.
Does the outboard rev like a slipping clutch on a car?
Does the outboard ever reach full revs?

The only thing I can think of is a slipping prop hub as has been mentioned before... but that should be so obvious from the sound.

[willk]

Max and Fenlander - I think you are wasting your breath here

[ferryden]

Originally Posted by willk

Max and Fenlander - I think you are wasting your breath here

..not sure what the comment's meant to mean Willk... yes I'm a noob, but we've gotta start somewhere...

Anyways, we are usually 2 up and are now pumped up with all air pressures to max recommended levels in handbook (and as per prior posts suggested)...using new guaged pump as recommended on here to do this. I do plan to take this with me to let out excess air next time I'm out later next week..

Reason I'm frustrated is I do know I should be up on the plane..I see smaller engines than mine up there with similar loads. As I'm sure on air pressures all round and have played with various trim settings the prop seems only other thing to go at but when had the engine serviced before taking it out the mechanic reckoned it was fine. Hence I reckon it can only be the engine now, which is obviously bad news for the wallet...

I've asnwered your questions below mate... ;-)

So what pressures are you calling max and how are you judging the pressure?
all air pressures pumped with guage to max recommended levels in handbook

What happens as you approach the transition speed (about 9mph) to plane?
doesn't get much beyond this speed tbh

Does the floor hump up in the middle, do the tubes start to fold/flex.
No

Does the outboard rev like a slipping clutch on a car?
Never.. feels quite smooth (but slow) ...

Does the outboard ever reach full revs?
..I don't have a tachometer, but does steadily rev up to max tiller 'fast setting'...

Cheers again...
Ferryden

[willk]

Originally Posted by ferryden

..not sure what the comment's meant to mean Willk... yes I'm a noob, but we've gotta start somewhere...

M'pologies - I think Fenlander and I read your post the same way - that you hadn't used a gauge - I see that I was mistaken.

It certainly does look like the motor, not the prop.

The big worry is lack of compression on one or both cylinders, but I think that even with poor compression, you should still get above 9mph? Anyone?

There is also the poss that the motor is not firing properly (or at all) on one of the two cylinders. I once neglected to replace a HT lead on mine and the result was very similar - displacement speeds that sounded kinda ok. I was amazed that the motor ran as smoothly as it did one one cylinder only.

Frankly, if you have checked the obvious stuff, a good mechanic is probably your next port of call. They'll check the compression and spark and whatever.

[ferryden]

No probs pal...I can only agree and that's why I'm stumped.

It wouldn't be so bad but I paid 260 notes to service the bloody thing after I'd bought it... I'm gonna go back there at the weekend.

..and I really have appreciated all the advice....good thing about problems is that they do force you to learn stuff!

:-)

[Festinghouse]

sorry if this sounds daft, but do you use launching wheels? if so did you have them lifted up out of the water? friend of mine was worried about the performance of his 15 on his zodiac 340 when i pointed out that he had left the wheels down!

[ferryden]

Yes....

but ..

Yes!!!
LOL!

[willk]

Yeah, I've done this too...

[Patrik]

Originally Posted by willk

Does the outboard rev like a slipping clutch on a car?

Now this is exactly what my engine just started doing (sorry for bringing it up in here but I was reading). It revs good and the engine sounds good, but I loose all speed when I come over 30-50% of the engine's capacity. And that's like, drop dead loose all speed.

It was working fine until I heard some kind of knock, and then this happened. And I didn't hit a rock...

I'm sorry to hear about these low speeds though! What engine is it? Perhaps there's some lock on it that restricts revving in neutral gear, and that now is coming on (faulty) even on forward? I found one of those on my engine, but I didn't have that problem. I just thought it could happen. Can you go as fast in reverse as forward? :o

[ferryden]

...old 80s MarinerW15 Patrik... a simple affair... unlikely to have any deliberate override mechanism...not as fast in reverse (thankfully), but have wondered if there is anything else acting as a rev limiter at the tiller end. Will try taking off hood and on the water and see if I can increase throttle direct engine end?...

[Patrik]

Always worth a try. Be careful if you're fingering inside the engine when it's on though, especially on the water... And don't run into anything Several reasons why people put the engines in a barrel

I have no idea how the mariner looks inside, but on the 70-80's evinrudes there's obviously some limiters of rev, for neutral and reverse. It's just like some pin or something that folds down when the gear switch isn't on forward. However, that was just a shot in the dark from me, I'm just a beginner myself.

[Mike B]

Before looking to replace engine I would have it in somewhere that can put it on a Dynometer.

From your first post it sounds like where you had it serviced didn't do this or they would be able to confirm the actual power output.

If I remember correctly Sam Speed Marine at Wotton under Edge (not too far from you) have a Dyno. I'm not connected with them just a happy customer.

Mike

[m chappelow]

i too recon this an engine problem rather than boat trim a 15 hp should make this fly ,

could be something as simple as a faulty spark plug ,,even if they are new ones ,i had a similar problem with a brand new engine ,,10 hours running from new ,,would start up and run fine all day but when just about to get on the plane the power would drop and seemed like cylinder was down ,
i checked plugs good strong spark, correct gap as i keep the correct feeler gauge in the tool kit and both cylinders were running fine ,what i dident see at first was on one cylinder the tiny insulater ceramic tip at the spark end was broken and once the engine had about half power it would vibrate down the electrode and the spark was then shorting out up inside the plug,
when i reduced power the insulater vibrated back and it started sparking again ,,new plug and it had full power and up on the plane again.

[ferryden]

Thanks all.... plugs are new... I was told by mechanic compression was good... will take back to nearest shop in Mallorca where its sitting right now...
:-)

[willk]

Another thought - have you checked if the throttle cable is actually pulling the the throttle lever on the engine to the fully open position? - the adjustment might be off/slipped...