I acquired a 2021 190 Montauk with Mercury 150 HP and 22 engine hours earlier this year. I use this boat in saltwater and flush and wash it after each use. Upon initially flushing the outboard, I noticed water coming from the telltale and lower unit. As of late, water from the telltale only comes out in dribs and drabs, then stops. While operating in water, the outboard is still performing normally with no overheating and strong telltale stream. The owner's manual is does not describe what to expect when flushing. I believe there should be water coming from the telltale during flushing.
I spoke with Mercury, and they indicate water should come from the telltale when flushing but not to the level of normal when in-water operation. At present I'm getting very little, if any water at the telltale while flushing. I'm interested in understanding what is normal while using the flush port and how to address the possible flushing obstruction. Thanks.
Mercury flush port and telltale water stream
Re: Mercury flush port and telltale water stream
Is your outboard engine running when operating on the hose adaptor for flushing?
Re: Mercury flush port and telltale water stream
The outboard is NOT running when using the flush port. I've verified this is correct in manual. The manual doesn't state where fresh water should exit when using the flush port. I assume both telltale and lower unit.
Re: Mercury flush port and telltale water stream
The absence of an overboard indicator stream or a decrease in flow rate from the overboard indicator stream when the engine is not running and water is being forced into the cooling system by a hose at a flush port compared to when the engine is running and there a strong stream or spray of water from the overboard confidence indicator nozzle might be due to the location in the cooling system at which the flow of water to the overboard indicator nozzle is taken from. The path for the water from the flushing port may not go immediately to the overboard indicator nozzle, so the flow rate from the overboard indicator stream won't be as strong as when the engine is running because of that.
According to your account of what a Mercury service dealer told you, a reduction in flow rate of water at the overboard indicator stream when the engine is not operating and water is being forced into the engine by a hose connected to a faucet seems normal.
Typically the strength of the overboard indicator stream flow is related to the water pressure in the cooling system. When the engine is operating at normal engine speeds, a strong flow at the overboard indicator should be seen. If the engine is not running, the amount of water being expelled at the overboard confidence stream nozzle will depend on the water pressure created by the water hose and the connection to the flushing port. Or, the water pressure available at the faucet you are using is not very high.
Regarding the possible presence of debris in the flushing port hose that connects to a garden hose that connects to a faucet to the flushing port, a simple way to back flush the flushing port MIGHT be to run the engine with the boat in the water, and then remove the cap on the flushing port. Any debris in the flushing port should be flushed out. But do not do this very long, as diverting a lot of cooling water away from the engine to travel overboard via the flushing port is probably going to cause the engine temperature to increase due to lack of cooling water volume.
According to your account of what a Mercury service dealer told you, a reduction in flow rate of water at the overboard indicator stream when the engine is not operating and water is being forced into the engine by a hose connected to a faucet seems normal.
Typically the strength of the overboard indicator stream flow is related to the water pressure in the cooling system. When the engine is operating at normal engine speeds, a strong flow at the overboard indicator should be seen. If the engine is not running, the amount of water being expelled at the overboard confidence stream nozzle will depend on the water pressure created by the water hose and the connection to the flushing port. Or, the water pressure available at the faucet you are using is not very high.
Regarding the possible presence of debris in the flushing port hose that connects to a garden hose that connects to a faucet to the flushing port, a simple way to back flush the flushing port MIGHT be to run the engine with the boat in the water, and then remove the cap on the flushing port. Any debris in the flushing port should be flushed out. But do not do this very long, as diverting a lot of cooling water away from the engine to travel overboard via the flushing port is probably going to cause the engine temperature to increase due to lack of cooling water volume.
Re: Mercury flush port and telltale water stream
jimh--thanks for your help.
After getting the engine up to operating temperature, I removed the flush port cap and released some noticeable pressure.
Although there is a check value, some warm water drained out then stopped.
The first attempt to flush resulted in the telltale spitting some water. However, a later second attempt produced a steady stream of water from the telltale.
After getting the engine up to operating temperature, I removed the flush port cap and released some noticeable pressure.
Although there is a check value, some warm water drained out then stopped.
The first attempt to flush resulted in the telltale spitting some water. However, a later second attempt produced a steady stream of water from the telltale.
Re: Mercury flush port and telltale water stream
Thanks for the follow-up report that twice trying to back flush debris in the flushing port seemed to improve the volume of water flow at the overboard indicator when using the flushing port.