Evinrude 115 ficht causing horrendus handling - WHY

[EDDYSTONE EEL]

Was hoping to pick your brains. I have a Ryds 550GTS which came with a 1993 Johnson 90hp and the boat went great, stable at any speed etc.

We replaced that with a larger Evinrude Ficht 115hp 2003. We fitted it in the same position as the 90hp as it matched right up but now were getting terrible stability, hanlding and performance.

Any ideas as to why it could be. When you have a driver and anyone sat up on the forward seats the boat wants to dive down left when you give it juice to the point where it could topple over if you keep up the speed

Its causing some real concern for the family (kids). It also wants to vere right when you let go of the wheel. We have tried doel fins, turning the skeg fin anode but still the same. Do we need to move the motor off-centre or up, down etc. The prop is in poor condition and in need of replacement, one of the blades has an inch chunk missing and the others have nicks in them - could this cause the problem.

Any advice would be great as if we cant sort it I'll have to get shot of it. cheers

 

[ab1]

Re: Evinrude 115 ficht causing horrendus handling - WHY

If your prop is really that chewed up then I would replace that first. You need some sort of baseline to start with before making adjustments and since you know that is bad any adjusting you do will be off again when you finally fix the prop. A 1" chunk is a pretty big deal. Start there, and then see what you get. Just my $.02 since I'm certainly no expert but I've seen bent or chewed props cause some really odd handling.

 

[jonesg]

Re: Evinrude 115 ficht causing horrendus handling - WHY

Wrong forum really, but I wouldn't run my old peice of junk outboard with a chunk missing from the prop. The dynamic imbalance imparted on the prop shaft can ruin bearings.

 

[Chinewalker]

Re: Evinrude 115 ficht causing horrendus handling - WHY

Have you tried trimming the motor up? The diving down phenomena sounds like it's trimmed too far under. The motor veering to the side also sounds like it's not where it wants to be, trim-wise.

 

[EDDYSTONE EEL]

Re: Evinrude 115 ficht causing horrendus handling - WHY

Thanks for the replies

Agreed the prop needs changing. I did not think it would affect the handling just the power, vibrations and of course bearings etc.

I'll get that changed and then see what happens. Does anyone think the motor itself may need moved off-center - what does that tend to do ?

Cheers

 

[Dhadley]

Re: Evinrude 115 ficht causing horrendus handling - WHY

What do you mean when you say it would "topple over" if you kept going? Also revist Chine's response about your trim angle. The newer motors have more trim range - negative and positive.

 

[noelm]

Re: Evinrude 115 ficht causing horrendus handling - WHY

I guess you have the correct length shaft? I have seen lots of funny things caused by people buying a used motor and it is (say) a 25" shaft, when they needed a 20, (or vice versa) might not be the problem but as mentioned, you need to base to start at, new prop, correct length shaft, trim working and we can go from there.

 

[Chinewalker]

Re: Evinrude 115 ficht causing horrendus handling - WHY

And no, you do not move the motor off-center...

 

[seahorse5]

Re: Evinrude 115 ficht causing horrendus handling - WHY

Is it possible that you installed a motor with a longer shaft length than the previous engine?


Where is the "cavitation plate" in relation to the keel at the transom? Is it above or below the bottom of the boat?