Yam 28 / 30? issues

[jonnyhas]

Hi Guys,

quick question to you all i have reciently purchased a sib wich came with what was describe as a 30 hp Yam, after reading a a bit on the net i am not sure exactly what it is as the cowling says 30 the only plate on it say 28, so am not sure it is a 2cyl but i also got with it a 2cyl 30AE wich is on the plate with no bottom leg??

Anyhoo the problem i have is starting and idling and re starting after stalling, when she starts from cold it takes a wee while but she gets going and works fine at throttle but dont like idling to much although she will sometimes and then cut out, if she does stall then it takes for ever to get her started again even when she is warm but when she gets going she is fine and you can go all day. its just un-nerving that she takes so long to get started again after she stalls, i have been looking at possibly cleaning the carbs make sure they are not gummed up, has anyone else any ideas as to what could be causing this.

any comments very welcome.

Regards
Jonny

[simsy]

Pilot air jet(s) setting should be at the recommended position (2.5 turns out???) and the jets the right size for a kick off, but not going to help if they are blocked up a bit with muck. I would fit new plugs and clean the carbs with air line etc. Then stage 2; look at compression and ignition timing.

[Nos4r2]

Originally Posted by simsy

Pilot air jet(s) setting should be at the recommended position (2.5 turns out???) and the jets the right size for a kick off, but not going to help if they are blocked up a bit with muck. I would fit new plugs and clean the carbs with air line etc. Then stage 2; look at compression and ignition timing.

I'd be doing the compression check 1st-it's quick and easy and tells you if you're wasting your time doing anything else.

[jonnyhas]

Thanks for the response what compression figure roughly should i be looking for? my brother has a gauge so would be a quick operation to carry out.

[Nos4r2]

Generally compression gauges aren't that accurately calibrated so you're looking for reading of within 10% of each other. Worry if it's below 100.

[jonnyhas]

thank you Simsy / Nos, checked the compression 140 & 138 on the other, stripped the carb cleaned / blew it out and she seams to be running fine, i run her stopped her and started perfectly i then left her for an hour cooling then tried with no choke or throttle and she started no probs at half the cord out, so hopefully that will be her now.

cheers guys!

[9D280]

The 28/ 30 thing may be down to the fact that in days of yore, the crank HP was usually quoted, but then it became illegal to quote anything other than HP at the prop.

Having said that, I was under the impression Yam always quoted prop HP......