Yamaha 5hp failure

tangerine

Well-Known Member
Joined
2 Jan 2008
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209
Location
hampshire uk
www.normanwhite.co.uk
I have had a most unfortunate experience with a so called marine engineer running a small two man business in Devon. Can anyone recommend a Yamaha outboard specialist in the Hampshire area. My 5 hp starts with difficulty and will stop after a couple minutes running. The engine has approximately 8 hrs running since new.
 
Out or interest, has it been sat unused for a while.

I only ask as my 4hp would only start and run on full choke and loads of revs. The main carb jet was completely rusted out as it had sat unused and the fuel in the carb bowl had gone bad.

New jets and a load of carb cleaner, runs a treat. Very simple little engine really.
 
If the engine has only done 8 hours and it's out of warranty then I would strip the carb and change the plug. Does the engine turn over? If a four stroke is laid on the wrong side then oil could get into all the wrong places and could need cleaning out.
 
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If you wanted to tackle this yourself this is what I would do I (my engine had the same symptoms you described). Drain and bin the fuel, remove the carb strip it down and give it a proper clean - if you have an airline that would be useful but not essential. Whilst the carb is off clean the tank to carb fuel pipe. Then re-assemble, re-fuel and see if she starts which it most likely will.

Then if its not going to be used for a while (a few weeks) before tuning off the engine switch off the fuel tap and allow engine to run on the remaining fuel in the carb/float chamber until it stalls. I found with my Yamaha if I left the fuel in the in the carb for a while it started to gum up the jets (hence some people reporting they need to pull out the choke to get it too run). I also installed an inline fuel filter as well - there is a fuel filter already but is quite small - and given the regular fill ups due to the small tank its easy for debris to get in and cause issues.

Since having cleaned the carb and adopted the above post-use process I haven't had an issues in 3 seasons - the time it let me down was on the Dart regatta weekend mid river, just before an air display, resulting in some high speed rowing action!
 
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