Laser 61

[Ashley Hunt]

I’m about to try running my old Laser .61 but no matter how hard I look I can’t find the running instructions that originally came with the engine. Can anyone help me with the settings for the high and low speed needle valves and any other advice on starting and running the engine. I’ve been able to get advice from Laser for the valve clearances and type of fuel but that was all. The engine dates from probably the late eighties.

[Martin Harris - Moderator]

You can't really specify any exact settings as all engines differ, both physically and due to different fuels and atmospheric conditions - hence the reason why adjustments are provided!

A good way to set for initial starting is to set the main needle a little more open than the expected running position to ensure adequate fuel will reach the low end needle - say 2 1/2 turns out - and then open the throttle enough to trap a 1.5 mm drill in the throttle barrel opening. Connect a short length of clean fuel tube to the inlet nipple and try to blow through it. Adjust the low end needle so that you just detect a small hiss and this should give you a starting point.

Once the engine is running, set the top end needle for peak rpm and then turn your attention to the low end. Once you have it idling, open the throttle...if it dies suddenly, the mixture is too lean, so richen [open] it until you get a smooth transition. If it burbles and eventually picks up, then weaken it.

Once the bottom end is OK, re-check the top end as adjusting the bottom end has an effect on the top and re-check the low end...repeat if necessary.

[Ashley Hunt]

Hi Martin.

That's exactly the information I was after, thanks very much.