1974 Mercury 4HP - random questions

Hello everyone,

First may I apologise for my ignorance. My teenage years were spent in much larger vessels with stern drives.

I recently purchased a small 12' boat with the above engine that needed "some repair". As I'm familiar with small 2 stroke engines I overhauled the carburettor. The impeller was broken so after a quick online search I replaced it. Gearbox oil has the slightest trace of water contamination which I assume is normal for a contraption its age.

Imagine my surprise when I primed and choked it and started first pull! The engine runs well with good throttle response when tested in my bin full of water. I just have a few questions.

It works well in forward and neutral but there's no reverse gear. Is this normal?

Are there any special maintenance requirements for an engine this old? It will have a fairly easy life in fresh water.

High octane fuel with synthetic 2 stroke mix at 50:1 OK? Seems to run well.

What on earth does the troll lever do?

Thanks in advance guys!

You put the lower unit on incorrectly--the splines on the shifter is off. This can be trouble since the connector is made to go one way only and you forced it together. When you drop the leg again, there's a strong possibility the shifter shaft will pull out of the lower unit, which will require a total rip down to fix it. I suggest you see what you have and get back to us.

Regular fuel and 50:1.

These are great running little motors that even changed my stubborn mind on singe cylinder motors (as in, if it's only running on one cylinder...)

Jeff

Hi Jeff and thank you for your reply.

I was careful not to force anything when re-installing the lower unit and not change gears while it was off. I'll have another look at it although it seems to be running well and lack of reverse isn't really an issue on such a small boat.

Will see what it's like when I have a moment to drop it again.