Proper way to flush a 2001 75HP Four-stroke Outboard

[Hossbot]

Hello all. I recently got a pontoon boat with a 2001 75HP four-stroke outboard. I found an owners manual online and purchased a service manual. I couldn't find info about flushing in the service manual, but the owners manual does explain it. It essentially says to connect a garden hose to the port on the back of the engine, turn faucet on half way, start engine and let it idle for 5 minutes.

I did this today, but afterwards, did some googling and you-tubing and there seems to be some mixed info. Some say to use ear muffs. Some say to not run the engine. Etc.

The garden hose port on the back of the engine covers the tell tale port. So water comes out the lower unit only. Like its reverse flushing or something.

Anyways, I just wanted to check that this really is the best way to flush this engine. Thanks!

 

[Texasmark]

I have no idea as to the internal engine plumbing for flushing ports. However, using muffs on the lower unit water intake ports is a sure-nuf full flush with temp monitoring to ensure that the engine has gotten hot enough to open the T stat. If it uses a high rpm bypass pop-off valve like 2 strokers, the hose water pressure and 1500 rpm ought to be enough to force that open.

 

[Hossbot]

Thanks! I think I might switch to using muffs, or just do both. On one hand, it feels weird running the water backwards, but on the other hand, it feels weird not doing it the way it was designed.