1992 Merc 60 was running great for about 5 minutes then it started to bog down. I was where I was going so I stopped it. I fished a while then it was time to go back.

It fired right up no problem and ran great for about 3-4 minutes and then it started bogging again. I couldn't get above 1800 rpm or it would bog and die.

I killed it and sat for a minute or two in the middle of the lake while I looked for anything obvious. I fired it up and it ran fine the last 1/2 mile to the ramp.

When I trailered it I found a disconnected tube. It is located on the transom side of the motor running from the bottom of the engine compartment to the top of the lower unit.

Two questions:
1 - What is that tube?
2 - Could it have caused the bogging problem?

Thanks in advance.

Sounds like the speedo tube. Check the fuel bulb, tank vent, fuel filter and fuel lines for a leak.

No leak but the fuel filter had two problems.

1. It was the wrong one. It had the one that was on it when I bought it 3 years ago. Apparently it was one for a much smaller motor.

2. It was full of what looked like rusty tobacco. I am ashamed to admit it but I haven't cleaned/emptied it since I bought it. Totally nasty.

Thanks for the help.

Tight lines Gary.