120 force doing strange things

[scubakidz]

We posted a message yesterday got some sugges. 12footer recomended a few things,I checked motor mounts they are all really tight. I replaced spark plugs after spraying engine tune thru carbs, also replaced hub in prop. My problem is when i have boat in water it runs great untill i hit 2000rpm then it seems like the trim is not holding emgine down on engine bracket. It seems to hop about 3 or 4 inches then slaps against transom. you can not get past 2000 rpm or it seems to get worse. It started with a small thump every once in a while, now its consistant, it seems like the prop is loosig grip. I dont know,. This is a twin trophy if that matters. Any help would be great Ill try anything, also this motor is on starboard side.

 

[clanton]

Re: 120 force doing strange things

I dont quite understand what motor is doing. Does it do this with motor trimed in? Is T%T working ok. Does it continue to kick up and slam down if you keep power on? Could be jumping out and in gear.

 

[evin300]

Re: 120 force doing strange things

I have never owned a twin set-up, but the fact that you mentioned it was a twin, will get you many more responces IMHO. Just some thoughts: A moter that is underway will apply enough pressure to the transom to keep itself steady, even with a faulty hydralic trim.<br /><br />In the case of two motors, if one is providing more thrust, it will tend to drag the other one along for the ride, therefore pulling it away from the transom.

 

[scubakidz]

Re: 120 force doing strange things

Thanks for the input. Never owned two outboard engines either but getting ideas to try and fix before taking to shop and loosing boat for a month.

 

[scubakidz]

Re: 120 force doing strange things

just wanted to update everyone i took the boat to the shop and they found the problem it was the clutch dog and forward drive gear in lower unit, teeth on gear were slighly worn down. well anyway just thought this may help someone out there....