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Jason
Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 16102
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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I have a mercury 3.3 hp 2-stroke outboard. Ihad to replace

Customer Question

I have a mercury 3.3 hp 2-stroke outboard.
Ihad to replace the pin on the propeller and ever since, when put in forward gear, the engine works fine at very low RPM.
As soon as I give it some trottle, it gets out of gear and the prop does not turn.
Any idea what is the cause?
Thanks
Submitted: 2 years ago.
Category: Boat
Expert:  Jason replied 2 years ago.

Hello my name is ***** ***** I speaking with?

All Mercurys are cataloged by serial number, can I get that number so I know exactly what it is you have.

Also, are you hearing any grinding noises?

Customer: replied 2 years ago.
Serial Number is : 0T249527
Model number is : 1-003201AKAnd I hear no grinding noise.
Expert:  Jason replied 2 years ago.

Got it. They make this engine 2 ways. The first way is with a fixed gear, where it is always in gear as soon as you start it. And then they make one with a shifter so you can shift between neutral and gear.

Which style do you have?

Also, did you replace the shear pin or did somebody else do it for you?

Customer: replied 2 years ago.
then they make one with a shifter so you can shift between neutral and gear.
This is the one I have."Also, did you replace the shear pin or did somebody else do it for you?
Yes somebody did and actually, that trouble started immediately after.
Expert:  Jason replied 2 years ago.

There are 2 pins on this propeller. There is an aft pin, towards the rear of the prop, and this is just a cotter pin. And there is a fore pin, in front of the prop, and this is the actual shear pin. Since you didn't do this yourself, do you know if somebody maybe changed just the cotter pin mistaking it for the shear pin?

Customer: replied 2 years ago.
I just removed the propeller to check and the shear pin as well as the cotter pin are in place
Expert:  Jason replied 2 years ago.

With the propeller on, can you turn it counter clockwise, or does it try to turn the engine over and give resistance to turning?

Customer: replied 2 years ago.
I can turn the prop forward and backward by hand and with the lever in forward position, I fell the piston moving and I hear the air coming out of the exhaust on the compression cycle.
Also as I said, If Istart the engine and keep the throttle very low ( at trolling speed), the prop will turn normally. But as soon as I will try to give it some throttle, it will disengage.
Expert:  Jason replied 2 years ago.

But when you turn the propeller over, you are also turning the engine over as well, is that right?

Customer: replied 2 years ago.
if it is in forward gear
Expert:  Jason replied 2 years ago.

Hmmmm.... Is there any history or backstory you can share with me on this? Why was the shear pin replaced in the first place?

This should be a simple issue but nothing is presenting itself as a simple answer yet. Did this engine work on this boat just fine before it hit whatever it hit?

Customer: replied 2 years ago.
Actually, although it is abit old, this engine is almost new.
It has very little hours on it.
The person was crossing a sandbar where the prop was hitting the sand when the shear pin broke.
He replaced it and the trouble started right there.
That is about all I know.
Expert:  Jason replied 2 years ago.

Is this your engine, or somebody elses?

Customer: replied 2 years ago.
This is my engine. My brother was runnng it at the time.
Expert:  Jason replied 2 years ago.

Is the engine still on the same boat that the accident happened on, or has it moved to a different boat?

Customer: replied 2 years ago.
This is a portable engine that is used for fishing on different lakes where there are different boats.
Expert:  Jason replied 2 years ago.

What i'm trying to figure out is if it is a boat issue. Where the motor is either not long enough for the boat it is mounted to. Or if there is some kind of hull defect dragging air under the boat. If either scenario is happening the propeller will get airbound, and loose it's bite in the water, causing it to blow out. That is why I am asking if it is on the same boat or not.

Has this engine ever worked correctly on the boat it is attached to now?

Customer: replied 2 years ago.
it was working perfectly on that boat.
Expert:  Jason replied 2 years ago.

But not on the boat it is on now, correct?

Customer: replied 2 years ago.
Sorry. I was not clear.
It is now on the same boat as it was on before.... when working perfectly right.
Expert:  Jason replied 2 years ago.

There is an angle adjustment between the clamp bracket. There is a rod that the weight of the outboard sits on, and that rod is adjustable by moving it from 1 hole to the next. Is the outboard in the full down/in setting? Or does is it sitting in a higher position?

Customer: replied 2 years ago.
Actually, on this engine there is no angle adjustment rod.And also, keep in mind that what happens is that as I give it some throttle and the rpm increases, the propeller stops turning.....like if a gear disengaged.
Expert:  Jason replied 2 years ago.

Is the prop actually not turning, or are you just not getting thrust from it? Are you witnessing the propeller actually coming to a stop?

Customer: replied 2 years ago.
I can see the propeller stopped.
Expert:  Jason replied 2 years ago.

Gotcha At this point there is going to be either a broken shaft or a broken clutch/gear, and the lower unit needs to get removed and opened up. Is that something you wanted to get into?

Customer: replied 2 years ago.
No. I will not get into that. I would doubt myself.....I will have to take it to the dealer I guess.
Expert:  Jason replied 2 years ago.

If you do end up having any further questions about this, or want to bounce something off of me after speaking with the dealer, feel free to reply back at any time. Questions never close out, and you are free to reply back even after doing the ratings.

Good luck!

Jason

Customer: replied 2 years ago.
Thanks
Expert:  Jason replied 2 years ago.

You are most welcome.