Merc 9.8 Throttle Doesn't Open

[atimm693]

I just bought a 14' Alumacraft that came with a 9.8hp Mercury,

The previous owner said that the motor will start right up but will not rev.

I poked around and noticed that the throttle will not go past the start position. The throttle blade and cables are free, but the ignition advance doesn't seem to want to turn.

Anyone ever ran into this issue? I'm thinking there may be a mud dauber nest in there.

 

[racerone]

Is the motor in forward during your test ??

 

[atimm693]

No, I didn't. I feel silly now because I didn't know it had an interlock. Put it in gear and the throttle works fine.

When you pump the primer fuel just sprays out of the vents in the fuel pump, and there was no diaphragm installed. The IPL shows a diaphragm, I think someone tried to rebuild it and left it out. Fuel is definitely not coming out of the overflow, so I know it's not the needle.

It did start for a minute and the water pump works, so that's a plus.

 

[atimm693]

I installed the missing diaphragm and it runs good now.

How much water should come out of the tell-tale? At idle it's not really a steady stream. Seems like plenty of water. If you slow the idle way down the stream starts to get a little steamy and slows down even more.

The outlet water is around 120*, feels like the hot water out of a sink. I checked areas around the engine and the hottest area was about 160*, just behind the cylinders on the right side. Cylinder areas were all around 130*. This was just running in a barrel, no load at idle.

An extra impeller was included, so I'm thinking I may put it in for good measure to prevent failures down the road.

 

[racerone]

In my opinion the impeller on those should be replaced every 2 or 3 years.---One of the worst designs.

 

[atimm693]

I pulled it apart and found nothing wrong, the impeller still looks just fine.

The lower shroud with the tell-tale nozzle was included but not installed. That's why the stream looked so funny, I installed the shroud and it looks normal now.

Turns out the included impeller was the wrong part anyway, which I had suspected since there are a couple different shaft diameters.

 

[60sboater]

What year is yours?