Yamaha Enduro 8hp Water Pump Problem PLEASE HELP!

bahama_boater

Recruit
Joined
Aug 9, 2012
Messages
3
Hello everyone! I am in Freeport, Bahamas, and I have an inflatable dinghy with a Yamaha 8hp Enduro 2stroke. The engine year is 2000, and I am having a problem with it. It was sitting in the bush at another house for about 2-3 years without use. Now, when i run it at idle, she runs fine, however when she speeds up to a higher RPM, it simply will not pump water. I have eliminated the possibility of it not getting water in the first place, as I have reved it up in neutral at the dock, and in a bucket and using muffs and in all cases it still will not pump water at high RPM's. At this point I am desperate, as my local Yamaha dealer has stated they have no idea what else to try, there is a new impeller in the motor also. If anyone else has this motor or similar with the same problem and has found a solution, I would greatly appreciate knowing it. I realize that this is not a very common engine, which is also part of my problem! This is also my first post on a boating forum, so please be kind!

Any help would be greatly appreciated!
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Re: Yamaha Enduro 8hp Water Pump Problem PLEASE HELP!

Maybe remove, inspect, clean or replace the thermostat and pressure control valve...may have salt/mineral/corrosion deposits in or around them. They can be cleaned with a mild acid if salt deposits are present. Are you sure that your tell-tale tube is not blocked with dirt/bugs/etc.?...insert a piece of wire or monofilament line into tell-tale to be sure it's open. If motor had a "new impeller" and was operated out of the water even for a short time, then impeller may be overheated and ruined. Good Luck!:)
 

bahama_boater

Recruit
Joined
Aug 9, 2012
Messages
3
Re: Yamaha Enduro 8hp Water Pump Problem PLEASE HELP!

Maybe remove, inspect, clean or replace the thermostat and pressure control valve...may have salt/mineral/corrosion deposits in or around them. They can be cleaned with a mild acid if salt deposits are present. Are you sure that your tell-tale tube is not blocked with dirt/bugs/etc.?...insert a piece of wire or monofilament line into tell-tale to be sure it's open. If motor had a "new impeller" and was operated out of the water even for a short time, then impeller may be overheated and ruined. Good Luck!:)

Thanks man! that helps alot! I really appreciate your help, and i will try that, and get back to you with the results...Thanks again!

-Matt
 

bahama_boater

Recruit
Joined
Aug 9, 2012
Messages
3
Re: Yamaha Enduro 8hp Water Pump Problem PLEASE HELP!

Okay, so i inspected the engine a little closer, and found a parts catalog online, and there appears to be a housing for a thermostat, and there also appears that this particular engine is supposed to have a thermostat, but when i opened the housing in the engine, it was empty and full of sand, dirt ect. is it possible that ordering and installing a thermostat, and cleaning out the housing may fix the problem?
 
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