selva 9.9 hp 2 stroke problem

[rob john buck]

Selva 9.9 hp 2 stroke problem
Can anyone help I brought this engine it has a spark, compression seams ok it sucks in and blows out ok it has fired up a few times but now no joy.
I took off fuel pipe going to carb it pumps petrol ok.
I have taken carb off and cleaned the bottom bell chamber has fuel in it.
Not sure what to try next i did try easy start still not firing.

Help Robin

[henryfreston]

I would clean the carb- take the carb off, take the bowl off then spray carb cleaner into all of the jets, put it back on and see ifit is better.

[colcreate]

Originally Posted by rob john buck

Selva 9.9 hp 2 stroke problem
Can anyone help I brought this engine it has a spark, compression seams ok it sucks in and blows out ok it has fired up a few times but now no joy.
I took off fuel pipe going to carb it pumps petrol ok.
I have taken carb off and cleaned the bottom bell chamber has fuel in it.
Not sure what to try next i did try easy start still not firing.

Help Robin

This is a twin cylinder so make sure the plug leads are on correctly and confirm you have a good spark. The idle screw on the carb should be about 1 1/4 turns out but note how yours is set by counting how many turns to screw in then you can return to this if needed. Fuel oil mixture is 2% oil to petrol don't get this wrong too much oil will make it extremely difficult to start and only use TC3W spec oil.

When cleaning the carb (Dellorto models) remove the main jet and soak in carb cleaner or at least neat fuel. The idle drillings in the Venturi can be poked through with strands of soft copper wire and or blown through with compressed air.

These engines like a lot of choke (virtually flood) with a bit of throttle until they fire then knock the choke off and open the throttle slightly. If you have flooded it shut the choke off and turn it over a good few times with the throttle wide open then try again.

If desperate and the above doesnt work remove plugs and squirt fuel mixture into bores. ReFit clean dry plugs with correct leads and give it full choke. It should at least start and try to run, failing that it needs a serious coat of looking at, pm me if you need more help or a parts list.

[rob john buck]

Thanks guys I will try out all the things you both suggested.I will let you know what happens.
It has started before but smoked the garage out and was revving very fast then cut out.
Rob.

[rob john buck]

Just cleaned the Carb with carb cleaner did spray all air hole and jets every hole I could see I checked spark plugs again good spark from both leads and plugs.
I did all of the comments but would not fire I even sprayed easy start in back of carb.
Could it be the compression I can fill the suck in and blow out from both holes. Help

[colcreate]

After trying to start it and failed have you checked to see if the spark plugs are wet?
If they are dry then you are not getting fuel through. Is the choke butterfly acting properly and completely closing?
Never needed easystart myself, as long as you have a reasonable spark and compression put a quick squirt of 50:1 petrol/oil mix down each plug hole (screw clean plugs back in) and give it a pull. It should at least splutter into life and then die but hopefully will run with a bit of throttle. Try this method with and without full choke.
I have had several Selva's, one bought as a non runner was backfiring because the flywheel key way had sheared and the timing was out, but that is an extreme case. Another with low compression on one cylinder still started OK but had no power.

Air leaks after carb ie, reed valve, carb or crankcase leaks will make it hard to start.

[rob john buck]

Will try this now thanks

[rob john buck]

I have put some drops of petrol down spark holes I have checked choke butterfly it opens and closes okhave spark from both leads I cleaned old sparks up and checked they has a spark because I checked new ones they are about 1/16th longer from nut to spark brought them from marine shop who compared old with the new ones.
tried with choke out and in and more revs.

[rob john buck]

Because this is not working petrol down spark hole and I do have a spark could it be compression.

[EnglishLes]

My first car in 1969 was a 1961 Fiat 500. Sometimes this was difficult to start so I used to take the plugs out and warm them on the gas stove for a few minutes - not red hot but uncomfortable to hold - this always used to do the trick. If you don't have a gas stove you could try a cooks gas flame thing, a weed burner or one of those DIY gas blow lamps.

[m chappelow]

[QUOTE="new ones they are about 1/16th longer from nut to spark brought them from marine shop who compared old with the new ones.
tried with choke out and in and more revs.[/QUOTE]

Could be that if the spark plugs are long reach ones the piston is touching the electrode & is closing the gap slightly .

[colcreate]

Spark plugs for a 1997/8 Selva 9.9 (in fact most models) is BOSCH W7B or CHAMPION L 87 or equivalents. 20thou gap is recommended but anything close except a dead short should at least fire.
A copy of the parts manuals is on my server here: http://www.avonsearider.co.uk/pdf/Se...S1997-1998.pdf
Might be useful for wiring diagram....
Owners manual here:
http://www.avonsearider.co.uk/pdf/OwnermanualNaxos.pdf
Check out the starting procedure!

A compression test would of course be handy and should be over 100psi and within say 10% of each other although even poor compression engines will at least fire up even if they wont run well. When trying to start before putting fuel in the bores were the plugs wet?

I'm going on holiday now so will not be posting much over the weekend.
Good luck.