Yamaha 55 tiller not reving at running temp

gofish206

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Joined
Nov 7, 2010
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3
Hello everyone thanks for looking at my thread. i have just recently purhcased a used Yamaha 55hp 2cyl outboard. I do not know much about the motor but it cranks and idles and revs just fine. But after it gets to running temp it will not rev up it just goes (duh,duh,duh,duh) almost like a limiter. you are still able to turn off and crank back up but it will not rev up. If you let it sit and cool back down it will crank and rev until it gets warmed up. I have no clue so any advice would be helpful thanks. I am pretty sure its a early 90's model.
 

99yam40

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Sep 7, 2008
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8,842
Re: Yamaha 55 tiller not reving at running temp

check to see if the over temperature alarm functions properly, sounds like it maybe coming in but the alarm buzzer is not working
 

gofish206

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Nov 7, 2010
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Re: Yamaha 55 tiller not reving at running temp

I will check that out thanks. i just took at look at the thermostat and the previous owner must have taken it out thier was nothing under the cover. I have checked the impelor and its good and it is peeing water why could it be overheating? Is that temp sensor located on the cylinder head. Thanks
 

99yam40

Fleet Admiral
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Sep 7, 2008
Messages
8,842
Re: Yamaha 55 tiller not reving at running temp

All water cooled motors need their thermostats in to get the motor up to the proper temp to burn the fuel properly and the restriction of it will force the water to circulate all through the motor properly, without it in there it can cause hot spots.
Good chance that yours was having problems and he disconnected the alarm and sold it. Could be blockage, bad pump(even if it looks good),etc

Best thing you can do is get a manual and read up on your motor and what it takes to do things .
Or you can do some searches on the web or this forum and see what all you can find
 

gofish206

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Nov 7, 2010
Messages
3
Re: Yamaha 55 tiller not reving at running temp

Ok. so i definatley have a cooling issue. I pulled the cylinder head cover off tonight and its ugly. I ran the engine in a barrel with the cover off and "no" water. I have ordered a manual so I hope i can get it figured out. should i remove the exhaust cover does this have anything to do with the cooling system being clogged. Thanks
 
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