Twin Honda 225

[oyvind]

I currently have a 30 ft CC with a pair of Honda 225 on a Stainless Marine outboard bracket and CMC lifts spinning a pair of 25' Hydromotives. She is a handfull, but I'm working on the setup.

Since I currently experience handling issues (she is very loose and I have to work the steering wheel a great deal at WOT ) and almost every Honda 225 in the states have the Sabre gearcarse installed (nosecone) due to very blunt gearcase, I am considering installing the Hydromotive OR the Bobs Machine Big Foot nosecone.

Shold I have the nosecones welded on (in addition to using epoxy), or is it OK to just use the epoxy? Which nosecone would you recommend? Inputs when it comes to improved handling? Already have a trim tank forward.

Thanks!

[Temporarily Insane]

Oyvind, Firstly Id like to welcome you to Boatmad.

With regards to the nose cone, DO NOT USE JUST EPOXY, itll come off and smack into your prop in a worse case scenario.

Weld the nose cone onto your gearbox. I understand that most or all of the UK Honda race boats run with the nose cone on.

Once the nosecone is welded on, file back the high spots and form a slight concave (so that the epoxy has a bit of bulk) along the join of the gearbox and nosecone. Give the area to be filled a good key, fill with the epoxy filler and then just use an emery board and feather from point to point and then paint.

Just be careful to tell the people who are welding your cone on that the casing isnt very thick so they dont weld through. This needs to be taken into account also when filing back.

Good luck

[red 5]

Hi, Rich how many gearbox's have you performed work on? Would you perhaps ream them out after welding or just deal with the white sticky glue getting all over your point. Do you prefere hand rubbing in preference to battery opperated device. And finally would you use lubrication. happy newyear old fella.

[Temporarily Insane]

Happy new year Steve ...........As you know a battery operated device is of preference........A lot less hassle

I hope you guys had a good un.

Have you sold your 25 yet?

[sinkunit0]

have a look on www.low-h2o.com. titus modifys the 225 cases

[scottyboy]

Interesting what they do with the cavitation plate! Wonder if it works on a merc box?

[sinkunit0]

Originally Posted by scottyboy

Interesting what they do with the cavitation plate! Wonder if it works on a merc box?

my thoughts exactly

[scottyboy]

What they do with the rougher underside and the water pick ups is true! Found that out in testing! The B23 is terrible for getting on the plane from stand still but i dont really wanna ruin a good box trying it out!

[sterling]

Tell your welder not to weld it all around ,just spots 50 mm long every 50 mm is enough,tell him to use a mig /mag weld machine ,a Tig brings to much heat ,cool down with every weld he laid down.
But befor you weld ,spend a long time to find out how you are going to keep it straith and true.
I did this about 30 times for lot of my boating buddies in the past ,this is how I did it .
Grind all the paint away with a 24 P disc grinder,also the inside of the cone .
take a small amount( 200 gram) Epoxy resin with micro balloons /filler material to make it thicker like body filler.
set the gearcase in a fixed stand with the propshaft down facing the ground.
put the epoxy into the cone ,and place the cone onto the lower,take a few straith edges ,and hold them along the gearcase housing ,measure the diameter gearcase lets say its 120 mm (example) you have to measure exactly 60 mm left /right between the straith edges and the center nose cone ,now measure from the edge that mounts to the exhaust housing to the center propshaft,and measure the same distance from center cone to surface that mounts to exhaust housing.
With the epoxy in place you can move the cone untill you satisfied ,and sure its straith /true.
next day you can weld without moving the cone ,welds will shrink and therefore pull the cone away ,the epoxy keeps it in placefor you.

good luck sterling

[Matt]

Was reading instructions for the hydromotive nosecones the other day and it say's DON'T weld it on.

[Tony Davis]

Epoxy is the way for bobs machine shop too. I've never had 1 come off!

[Matt]

http://www.rexmar.com/page144.html
&
http://www.rexmar.com/page145.html

[jonny12t]

a couple of guys in the Honda 225 fleet have had them come off and they all weld them on now. and you are right about the thickness some have had the legs leaking oil.

[Irapesheep]

If you are going to weld it, use GTAW (tig)..

Its true its hotter than GMAW (MIG/MAG) but it is the ONLY way to weld aluminium sufficiently strong since all parent material will be bonded. It will also make cleaning up and sanding a lot less labor intensive.

An experienced welder can and will set amperage lower than needed. This will minimize distortion and you can be sure the weld will not be brittle (oxigen inclusion) unlike mig/mag Alu.

Do a FULL weld, tackwelding it doesn't ensure a good and healthy bond because the heat affected zone in aluminium is in some alu compositions 50% less strong.

Tackweld it in place by alternating each side without filler. Then work your way around (if filler is necessary use low temp melting filler, minimum risk of heat/stress cracking).

An experienced tigger will know what to do. 30 amps per mm=> if its 4mm thick, take AC, pulse (reducing heat imput), +/- 110 amp. Balance set to -60 to get good penetration <=> cleaning/oxide removal. Make sure its clean and don't use regular abrasives since these will contaminate the aluminium. Weld immediately after preparations.

[sterling]

A fully tig welded cone is probably going to distord,remember the cone material is 12 -14mm thick ,and the lower unit is a thick casting too,therefore you will need a high ampere machine that will bring a massive amount heat into the casing.

Bob,s machine shop at FL does also 5 mig welds +- 5 cm long,on each side ,they do that with a complete lower with internals.
I visit their shop several times ,and can tell they can have a full time job doing nosecone installs.

I don,t know what will happen when a casing is deformed during a high heat welding proces ,but can imagine the front bearing ring that sits into the alu housing can easily become oval during shrinking of the material.

Don,t forget to drill a small hole into the normal sidewaterinlet ,(if you weld it shut)
It allows the water to pour out ,so it can,t expand during freezing.

Sterling

[Irapesheep]

A huge U-groove/ Multi-pass and a big heat sink are your friends

Remember Mig also transfers heat. I have cut 25" midsections down to 15 and welded them completely shut without any distortion. Today they still hold without stress cracks or any other sort of fatigue. The first one who does this MIG style.. i say good luck! I'll support your wife and kids when things go wrong.

A full TIG weld is a hell of a lot stronger even with 50% penetration than a large tack weld going through all the way and causing stress on the pieces where they are attached to each other. They do this probably because it is 'sufficiently" strong a lot faster and way easier. I always want it to be safe.

Once you know your TIG, you never ever need MIG.

It's al about practice. So do it your way but dont come near me. I don't like cast alu being swung at my boat.

[sterling]

I think than you better not go out on the water again,because all the nose cones you see people using are mig welded (not around but tacked)
Or they just used epoxy only.

Like I said ,at Bob,s machine shop they made probably a few ten thousand cones like this,and they send them away with a warranty.

They also have an explanation as to why not weld them around.

look at his site ,its probably there,also look at Tooter,s site they do it exactly the same,Tooter does all the fast cones for :stroker ,allisons ,hydrostreams,bullets etc.
They have boats run 117 mph+ with a cone like that.

I saw at Bertels a few years ago a fully tig welded 20 inch open exhaust for a V6 omc ,and it was coming apart,all the welds were broken.

sterling

[Irapesheep]

Like i said, do it your way.. but stay out of my vicinity!

[sterling]

Ok I,II come not close to you.

sterling