1800 Sportster Revival

[Jimmy in NC]

Trying to revive a 1800 Sportster with the M2 Merc. Been parked a few years but when parked was fine other than a fuel gauge that did not work. Water hooked to the port and she fires up fine but after about 5 minutes she triggers an overheat alarm. Disconnecting the starboard temp sensor turns the alarm off so it is clearly an over heat. Pulled the vent off the head and it flows water fine. With the vent off the top of the head I get no water out of it with the motor running. Kind of at a loss where to go next. The starboard bank clearly get hotter than the port.

 

[ripcuda]

This line circled is goes to a tell-tale (pisser) overboard. Ensure this line is not clogged (think mud dobber). It is the top of the head vent to allow the trapped air out... and once the air is out it creates the tell-tale. If this line is blocked it can cause that port bank to get hot.

 

[Tim75]

This line circled is goes to a tell-tale (pisser) overboard. Ensure this line is not clogged (think mud dobber). It is the top of the head vent to allow the trapped air out... and once the air is out it creates the tell-tale. If this line is blocked it can cause that port bank to get hot.
View attachment 58855

Are you testing the water flow on a hose or in the water?
On a hose, a lot of the water is wasted back through the jet tunnel. If you don't have lots of flow, you may not get water out of the pee hole. Bug debris in the pee hole hose is indeed a common problem. If this hose is not clear, it could actually cost you a melted piston.

Worst case- you could have sediment in the water jacket passages.

 

[Jimmy in NC]

This line circled is goes to a tell-tale (pisser) overboard. Ensure this line is not clogged (think mud dobber). It is the top of the head vent to allow the trapped air out... and once the air is out it creates the tell-tale. If this line is blocked it can cause that port bank to get hot.
View attachment 58855

Pulled the vent first and cleared air through it and then flowed water through it. The tell tale is clear.


I then flowed water back down the head until it dumped out the bottom of the jet. I'd say the water jackets are clear too.

 

[Jimmy in NC]

Are you testing the water flow on a hose or in the water?
On a hose, a lot of the water is wasted back through the jet tunnel. If you don't have lots of flow, you may not get water out of the pee hole. Bug debris in the pee hole hose is indeed a common problem. If this hose is not clear, it could actually cost you a melted piston.

Worst case- you could have sediment in the water jacket passages.

Testing on a garden hose. I think I simply do not have enough flow to push water through the system off my hose bib. Running the motor with the tell tale adapter removed from the head I still got nothing out of the head.. the tell tale hose / thruhull is not the issuse. I am 95% sure it is just a supply slow issue. Need to tow it to a ramp just to set it in the water and check flow.