Whats wrong with my engine?

[davis]

Thats a very generous offer Outreach , I would like to get sorted and would be willing to pay but do you think it could be an ongoing thing if there is a design fault? I stripped it down again yesterday ,left it soaking in petrol overnight and reassembled again today , pulled the cord and it started second pull ,ran for a short while then died again and wouldnt start, so at this stage i was thinking of just buying a new carb and fitting it, do you know how much a new carb would be.

[MOS]

Originally Posted by davis

Thats a very generous offer Outreach , I would like to get sorted and would be willing to pay but do you think it could be an ongoing thing if there is a design fault? I stripped it down again yesterday ,left it soaking in petrol overnight and reassembled again today , pulled the cord and it started second pull ,ran for a short while then died again and wouldnt start, so at this stage i was thinking of just buying a new carb and fitting it, do you know how much a new carb would be.

A new carb is about £115... - Not cheap

Do you know anyone else with a F4AMH... If so, ask if you can swap carbs and see if the problem persists... Also, Outreach is offering a ultrasound clean for free which is very good and I would try this first...

Also, have you changed the BR6HS plug for a new one... This could also be you're issue if you allowed the carb to soak in fuel it should run better than before!

[davis]

I havent changed the sparkplug just put a new one in in september, but will give it a try to see will it make a differance, if not i will probably take Outboard up on his offer , I wouldnt bring it back to where I bought it as it probably be cheaper to buy a new engine . I have to thank everyone for the help and advice they have given me , very helpful people on this site.

[outboardtech]

Lets try and clean that little fella out with the cleaner , If that dosent work then I can probably find a newer one off an engine and post that to you. You definetly have a fuel issue.quick test disconnect the fuel line goin to the carb and pull it over and see if fuel is coming spurting out , could also be FLOAT LEVEL have had a few of these in the field.

NEW CARB - PART NUMBER - 67D - 14301-22 - £226.88 + VAT

POP it in the post to me and I will put it in the cleaner for you and test it on another engine I have before posting it back too you.

PM SENT

[mike-m]

Hi

Have been reading this thread with some interest as I first saw it the day after I ordered a new Yamaha 4 stroke (the A series, not the newer B series)!!

Talking to a few techie types, it appears that with the leaner burn and finer jets on these small four strokes, it is common for water contamination of fuel to cause these problems.

Have you tried cleaning out the fuel tank thoroughly and refilling with fresh petrol? Fuel is becoming more hygroscopic as time goes by and will attract water the longer it is left.

I sincerely hope it is just a simple problem, else I will be feeling a bit sick when my new Yamaha stops working!

Good luck!!

Mike

[davis]

Hi mike , yes tried new fuel and cleaned the carb a few times. This engine has hardly been used as it is a backup for my main engine, thats why i went for a Yamaha thought I wouldnt have a problem with them. I hope your one is a different carb and this doesnt happen to you, however I have had great help on here and have even learned a little, regards.