Honwave 3.8 engine compatibility? - Page 2

Max... · 15 July 2014, 06:47

I would not cut it down, it will murder it's resale value, just sell it and get an Aerotec or other SIB that will not have these issues.

The Honwave transom is plywood like all SIB's, with a sheathing of plastic or similar.

Landlockedpirate · 15 July 2014, 06:59

Quote:

Originally Posted by beerbelly

the honwave transom is fibreglass not plywood not sure if cutting it is a sensible option.i think this is a designe flaw in the 3.8 drop down to a 3.2 they apparently don't suffer this problem

They do im afraid, not as much as the 3.8, but there is still a pronounced hump in the floor with max engine and heavily loaded.

warder54 · 15 July 2014, 08:44

I had this problem with my 3.8 too. Parsun 9.8 4 stroke short shaft, cavitation when coming onto the plane. Now sorted having remembered to change trim setting to 2nd hole from 3rd!! (My 14' portabote needed this setting) and topping up deck pressure after sitting in water for 10 min or so. she now gets on the plane quickly with +/- 300kg (2 + fuel + gear) and balanced out. could not believe how quick she was with the Parsun either, I was thinking of getting a heavier 15 next year but will now stick with this as it's quick enough and very economical/reliable. Plus I have a Smartwave XL 490 centre console on order for longer trips out and fun with more on board.
Here is my rig in the water at Ferryden Montrose waiting on my mate with the last of the gear.

Max... · 15 July 2014, 11:26

Quote:

Originally Posted by warder54

I had this problem with my 3.8 too. Parsun 9.8 4 stroke short shaft, cavitation when coming onto the plane. Now sorted having remembered to change trim setting to 2nd hole from 3rd!! (My 14' portabote needed this setting) and topping up deck pressure after sitting in water for 10 min or so. she now gets on the plane quickly with +/- 300kg (2 + fuel + gear) and balanced out. could not believe how quick she was with the Parsun either, I was thinking of getting a heavier 15 next year but will now stick with this as it's quick enough and very economical/reliable. Plus I have a Smartwave XL 490 centre console on order for longer trips out and fun with more on board.
Here is my rig in the water at Ferryden Montrose waiting on my mate with the last of the gear.

That's *remarkable* performance from a heavy low powered engine on a very heavily loaded large SIB. Would have thought if you add a console and even *more* load you'll be like a slug in treacle.

Does not seem representative of most of us on here......

In comparison my airfloor Zodiac (30kg boat) with a 9.8 Tohatsu (26 kg engine) was fine with me + child and light load (total load about 125kg) but add wife and other child (so total about 200kg) and major weight shift was needed to get on the plane.

My Bombard with Mariner 15 (lightest 2 stroke 15 available) pops up very quickly on the plane with the 125 kg load, not tried it with more weight yet.

Just amazed at what is reported on here from some SIB owners.

Landlockedpirate · 15 July 2014, 12:45

A bit of thread drift.

Just been for a look round the Parsun website, given the above performance I was thinking of ordering a 9.8 so my son can mono ski off the Futura

Anyway, came across this via Bill Higham, looks familiar doesnt it?

Buy Parsun parsun 9.8hp 2 stroke short shaft 9.8HP Outboard at Bill Higham Marine

warder54 · 15 July 2014, 13:55

Ok, just had a recalc on weight, my guestimate of 300kg was way over the top!

probably nearer 210kg. as for speed - not measured but much quicker than I was expecting from this set up but fast enough for my needs. Certainly skimmed over the surface nicely and sounded like it was near max revs at WOT (never managed this on the Portabote)
Had my mate near back to start then shift forward as we moved away - worked well.
Hope that is clearer for all.

Sailpower · 15 July 2014, 13:57

Quote:

Originally Posted by warder54

I had this problem with my 3.8 too. Parsun 9.8 4 stroke short shaft, cavitation when coming onto the plane. Now sorted having remembered to change trim setting to 2nd hole from 3rd!! (My 14' portabote needed this setting) and topping up deck pressure after sitting in water for 10 min or so. she now gets on the plane quickly with +/- 300kg (2 + fuel + gear) and balanced out. could not believe how quick she was with the Parsun either, I was thinking of getting a heavier 15 next year but will now stick with this as it's quick enough and very economical/reliable. Plus I have a Smartwave XL 490 centre console on order for longer trips out and fun with more on board.
Here is my rig in the water at Ferryden Montrose waiting on my mate with the last of the gear.

Thank, good to know its not just me. I've been running it on the second hole as that's where it seemed to be most vertical when level. maybe its more about the inflation but it definitely feels like the prop should be deeper as Locozodiac mentioned. Nice looking rig btw!

warder54 · 15 July 2014, 14:03

Cheers Sailpower, got her new in March as a 60th birthday treat to myself. Paid £1011 including delivery. Sold the Portabote (I loved it - wife hated it -"not getting me in an origami boat!")
Kept the Parsun from that set up and I'm now happy with the current combo. May however think about a 15 next year - never totally satisfied!!!

Sailpower · 15 July 2014, 14:36

Just looking at the weights of these Parsun engines (don't know how they compare to other modern motors) but they seem nice and light - the 4 stroke 9.8 is around the same as the old Johnson 9.9/15 2 stroke that I'm using - the 2 stroke Parsun even lighter.

The old Johnson suits my level of mechanical understanding of 2 strokes - no ignition timing to fuss with or valves/belt drives but the 4 strokes are undeniably cleaner and qieter.

slate1234 · 15 July 2014, 16:15

I have the same problem with cavitation / ventilation on a sunsport 3.2m sib and 9.8 tohatsu 2st , I have cut 30mm out of the transom it helped when I am fishing on my own it runs like a dream but as soon as I add another person It starts to cavitate, I have tried shimming the outboard back up but with no luck, I was chatting to a guy fishing of llandullas last week and he recons I need an ali / wood floor and my problems will be solved, I am looking out for one and will report back with the results

Max... · 15 July 2014, 17:18

Most of us have the opposite problem on SIB's and you need to add a wooden spacer block to raise the engine 1" or so. Certainly on the Aerotec and Zodiacs this is essential.

Best way to measure the set up is to get a cheap tiny tach off eBay (about £10) and measure the RPM at WOT with this and the speed with a GPS to fine tune trim and engine height.

Having said that 9/10 postion 2 is always the one and a block is needed as above.

Did mine last week and position (1) got me 5450 rpm and 17.5 kts or so, position (3) 5650 rpm and 18 kts (but horrible to get on plane due to raised bow) but position 2 wins at 5750 rpm and maxed out briefly at 19 kts.

bmb779 · 11 July 2018, 22:01

Use a motorbike battery

Quote:

Originally Posted by Fenlander

>>>>I got the car battery clip on version

Then you have the answer... a £15 generic 12v battery for alarm systems etc from Ebay. My Bravo has a side pocket in the case this will fit into. A full charge from a small battery will only just pump up the boat but is fine for topping up.

BoatyMcRibFace · 30 June 2020, 10:36

Great thread, extremely helpful in describing my problem. Just purchased honwave 38 and lovely 4 stroke yamaha 9.9hp. Had the cavitation issues described. I adjusted to all 4 trim settings to no avail. Feel sure it's the pressure drop issue. I have a 12v cigarette lighter sevylor pump. I don't really want to take a pump and battery out with me, has anyone tried over pressurizing at initial set up? I don't want to abuse my nice sib but it must have a much higher tolerance than the recommended pressure?

Fenlander · 30 June 2020, 10:48

Your pump will be heating the air and there will be extra cooling when put in the cold water. So you do need to recheck and likely inflate a bit more when it's been sitting in the water for a few minutes. Once you get a feel for your particular outfit you can over inflate this small amount initially to avoid the top up need.

Those Honwave floors can turn to jelly when down on pressure.

Re taking a pump I hope you take a manual one with you... a slow loss or accidental brief loss can happen and you need to be able to re-inflate.

BoatyMcRibFace · 30 June 2020, 11:13

Those Honwave floors can turn to jelly when down on pressure.

Re taking a pump I hope you take a manual one with you... a slow loss or accidental brief loss can happen and you need to be able to re-inflate.[/QUOTE]

I haven't been taking anything with me! Only been up the river and figure I'll just drive to the bank. I can't get the boat anywhere near correct pressure with the official bellow footpump supplied

Fenlander · 01 July 2020, 09:22

>>>can't get the boat anywhere near correct pressure with the official bellow footpump supplied

Folks do say this often re the Honwave pump... my Honwave was an alloy floor and the bellows pump was just OK for LP.

The Bravo brand bellows pump suppled with my Aerotec will get the HP floor up to pressure OK...

https://www.force4.co.uk/item/Bravo/...p-65-15Ltr/E5W

But some folks prefer and swear by a stirrup type pump.

A compact emergency one...

https://www.force4.co.uk/item/Bravo/...p-2x1100cc/W36

or the standard type if 0.8bar is sufficient...

https://www.force4.co.uk/item/Bravo/...p-2x2000cc/E60

BoatyMcRibFace · 01 July 2020, 09:36

Thanks for that. I do actually have the bravo bellows pump already. Two of us pumping at the same time but didn't notice it being better. Will give it another go.
My wife has just purchased a SUP with stirrup pump so got some options at least!
I have also seen you can get crocodile clip to cigarette lighter adaptor if I want to spend £15 on little 12v battery and use sevylor electric pump.
Thought the sib set up would be simple but still learning plenty!

Going to launch it in Poole harbour this weekend weather permitting and leave it bobbing for 15 minutes then wheel it back in and pump from the car I think

Fenlander · 01 July 2020, 09:54

Are you taking the black plug out of the Bravo to use the second stage? Agreed it takes loads of foot strokes but ours always gets to 0.8bar plus.

I always use a small battery now for my elec pump to remove the need to be close to the car which increases flexibility at setup time when it's crowded.

BoatyMcRibFace · 01 July 2020, 09:58

Quote:

Originally Posted by Fenlander

Are you taking the black plug out of the Bravo to use the second stage? Agreed it takes loads of foot strokes but ours always gets to 0.8bar plus.

I always use a small battery now for my elec pump to remove the need to be close to the car which increases flexibility at setup time when it's crowded.

Errr nope! It's a bigger model but not sure which one
Will investigate......

Fenlander · 01 July 2020, 10:46

If your Bravo footpump looks any different to the one below it is likely to be a LP model max 0.4-0.5bar. You need the HP one as in the image and to reach the HP stage you pull out the central black plug.

As you note there is a lot of detail in this apparent easy blow up and go boating lark!