Honda 4 stroke 90hp on 18ft Cheiftain

[fshndad]

Guys I've got a 90hp honda and I've mounted it on the boat and notice that is is flexes a bit with the heavier motor. I've had a 70 suzuki 4 stroke which weight about 330 lbs and it didn't flex this much. The honda weights about 380lbs. Anyone out there running a honda 90 on their 18' aluminium boat.

This is my first aluminum boat. is it normal to have any flexing?

 

[g0nef1sshn]

Im no expert, but i know pics of the transom and info regarding when the last rebuild of it was and what method was used to do it for these more experienced guys to able to give you some advice.

 

[dozerII]

You shouldn't be getting any flexing in the transom, I believe the hull is rated for a 120-140hp O/B If it's flexing it may be time to replace the transom, check the knee brace closely for cracks or loose rivets and bolts. Like g0ne said post up some pictures.

 

[Watermann]

^^^^ Absolutely! The transom in your Chief shouldn't have any flex even with a larger motor than the 90. Weight of the OB is secondary to the HP. If there's transom flexing then you have some work to do. You should also be using a motor toter / transom saver to help with the OB bounce while trailering.

Yes pics please.

 

[classiccat]

+1...transom replacement is the remedy. Good luck!

 

[fshndad]

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Sorry for the bad Pictures. Not much room in the barn.

 

[fshndad]

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Also, the Transom was redone in 07. boat never left outside in the weather.

 

[fshndad]

Forgot to mention most of the flexing is up at the top.

 

[Watermann]

Also, the Transom was redone in 07. boat never left outside in the weather.

The transom wood doesn't look bad in the pic but... Check the condition of the knee brace and the wood under the splashwell. Did you do the transom replacement?

A word of advice, don't put those drain plugs in the splashwell drain tube holes unless you want to meet Davey Jones.

 

[fshndad]

Thanks Watermann. Those were from the drain plug. I just leave them up there. I leave the splashwell drains open. I forgot to check the knee brace. will tonight.

 

[g0nef1sshn]

If the flexing in at the top, that makes me think to check the bolts through the transom on the port and starboard sides. maybe the hard to see/get to ones at the top have loosened or the wood at the nuts has rotted allowing the nut to sink into it with the force of the motor? Just a thought...

 

[dozerII]

The original transom was a three piece affair, the main lower part, then the upper corners were just set in on top from the factory. Most everyone makes the replacement, in one piece so the whole transom takes the stresses, if your transom was replaced in three pieces it could be part of the problem.