Yam 55 Fun - Page 2

SimonStDavids · 14 April 2014, 02:42

Thanks, at the moment I have a 13P.

Have to check on diameter but from memory 11 and a bit

RIB-Teccie · 14 April 2014, 08:05

That is the standard prop, the best one to start with.

SimonStDavids · 14 April 2014, 22:47

Well I had a nightmare

The engine is running like a bag of nails, and I am not sure why...

Left it idling against the quay whilst I took the trailer away and all was well, came back and plodded down the harbour and out to sea, all was good so opened it up, it ran wall but after about 5 mins started to miss a bit, so I limped back into the harbour. Checked everything obvious and changed the top plug (didn't have the right spanner for the bottom one) and tried again, it ran ok for 5 to 10 mins then the same again!!!

I am a bit perplexed, I'll swop the bottom plug too, but the top one looked good when it came out and I don't think it's fuel related, so I guess electrical, any suggestions where to try first or the best way to diagnose, it seemed fine running on muffs before...

RIB-Teccie · 14 April 2014, 22:55

1) Have the carbs been sitting with dirty fuel over the winter?
2) Is there spark on both plugs
3) Does fuel bulb prime up firm?
4) Does the magneto move freely
5) Has timing or carb settings been tampered with.
6) Any fuel leaks (float height)
7) Check for broken wires where they enter magneto.

RIB-Teccie · 14 April 2014, 22:58

If it is idling and then drops a pot, corrects itself and does the same again, it could be a coil, it's unlikely but I have seen it. If you want to PM me your number, I can call to assist over the phone.

9D280 · 15 April 2014, 13:30

...or the HT lead.

go- no go does sound electrical - and to put this in perspective the HT leads are running High voltage high frequency - it doesnlt take much for the insulation to break down.....

....which brings s back round to your lower plug!

Thing with a 2 cyl is if one dies or part dies it really does run like a bag of nails. My old one was like a new engine after I changed the plugs.

Damianfishy · 15 April 2014, 14:07

I used to have a 55 mariner I think same engine block, I had countless problems with mine, I would imagine you have a coil down/running on 1 cylinder, check for spark on each cylinder if no spark swap the coils round. It could be a simple spark plug though so swap them around also.

Hope you get it fixed