Mariner 40hp, irregular running

[Codbasher]

I have a Mariner 40hp, 2stroke, 2 cylinder, apx mid 80's. Up to now has been very reliable, but took it out today, started no probs, ticked over sweet, and off we went, then it cuts back to lower revs, then up again then back, it never cut out, but was hunting for revs all the time, but would tick over and start no problem. Sounded like fuel starvation, but all seemed OK in that department, dunno? Any help suggestions gratefully accepted, please feel free to e-mail if you wish. <br /><br />First time poster so please be gentle

 

[Elmer Fudge]

Re: Mariner 40hp, irregular running

I was going to say fuel pump diaphram,but i'm more inclined to think that it is possible that your fuel tank is not venting properly.<br />Are you using fresh gas?

 

[Codbasher]

Re: Mariner 40hp, irregular running

Cheers for the reply, tank seems to be venting OK, BUT the petrol (Gas, sorry Im English) is a year old, seeing as I have been in hospital for 7 Months the boat has not been used, but I did take it out 4 weeks ago with no problems. I was trying to burn the last of the old gas off before I refill the tanks ready for the Spring/Summer. May be best to change pump diaphram and try fresh fuel and spark plugs I guess.

 

[Elmer Fudge]

Re: Mariner 40hp, irregular running

I would do a decarb as well,since the motor was idle for quite some time .