J2 won't start - help needed

[Guest]

Hi All,

 

I am trying to get the lump working after fitting replacement heads.

 

Tried last Friday and noticed that there was potentially an air leak from the spark plug combustion chamber on No 2 cylinder. I could not work out how to get this off to have a look.

 

I have a decent spark, new plugs etc. It di fire once for about 10 seconds a month or 2 ago and then stopped, I have not been able to fire it again since.

 

Is there anyone who could come to the boat and have a good look and help me figure out what is wrong. Our good friend Dick Gobel is out of action with a dodgy knee so reluctant to ask him.

Willing to pay for the the time and effort.

 

I really need it sorting as the boat is up for sale.

 

Please PM me if you can help.

 

Many thanks

 

Paul

[David Mack]

 

10 minutes ago, Badminton355 said:

Is there anyone who could come to the boat and have a good look and help me figure out what is wrong.

Might help if you said where the boat is.

[Guest]

The boat is moored at Heritage marina, Scholar Green.

[BEngo]

I am in Aylesbury, which is a bit far I am afraid.

 

Is the impulse drive working? Loud clack when you turn the engine over by hand?

I assume you have a good fat spark from the magneto.

 

The engine will generally run

and start OK with a slight leak under the combustion chambers, but If the combustion chambers really  need to come off they are not hard to remove.

 

Take the rocker covers and induction  pipes off.

Remove the starting valve rocker.

Remove the nuts on the starting valve.

Remove the starting valve spring.

Remove the 4 combustion chamber bolts.  Lift the chamber off the starting valve.

 

Reassemble is the reverse of removal.  Seal the chamber to head joint with Hylomar or   Wellseal.  There is no gasket.

 

 Your symptoms shout out to me of dirty plugs and a part blocked carb jet, or very stale petrol.

 

Give the plugs a really really good clean and then roast the tip in a gas flame ( on the cooker if 'er indoors is not looking).  Try to get Champion K97F plugs as they have 3 electrodes and don't soot up badly.  Rotate the carb upside down by loosening slightly on the clamps.

Take the plug out of the base.

Remove the jet ( hexagonal thing with a tiny hole.)  A small socket or box spanner is needed.   BLOW the little hole clear using an air duster or similar.  Don't poke it with wire, but a brush bristle is OK.

Refit jet.

Refit carb plug.

Turn carb upright and tighten clamps.

 

Make sure you have fresh petrol.

 

N

 

 

 

 

[MtB]

1 hour ago, BEngo said:

or very stale petrol.

 

 

This is a classic rookie mistake. The most volatile fractions are added to petrol to make starting easy but they can evaporate away in as little as a month or two. Try it with newly-purchased petrol.

 

DAMHIK.

 

 

 

 

[jonesthenuke]

22 minutes ago, MtB said:

 

This is a classic rookie mistake. The most volatile fractions are added to petrol to make starting easy but they can evaporate away in as little as a month or two. Try it with newly-purchased petrol.

 

DAMHIK.

 

 

 

 

And the modern  so called "petrol" is even worse due to the ethanol that is now added. Its the bane of generators, mowers, strimmers which are used only occasionally.

[Stilllearning]

1 hour ago, jonesthenuke said:

And the modern  so called "petrol" is even worse due to the ethanol that is now added. Its the bane of generators, mowers, strimmers which are used only occasionally.

I suppose that it might depend on how it is stored. I recently started up the brushcutter after about a year, and it started second pull and ran perfectly.

[dave moore]

Just out of interest, when we started our J3 on petrol, I was advised by one of the Gardner family that the old fashioned 4 star was preferable to unleaded, having a higher octane rating. It made starting easier, though we converted to thermostart soon afterwards. I’m aware of the stale petrol issue.

[MtB]

My K1 and K2 both now a pig to start on petrol. Maybe the change in petrol formulation is the reason.

 

They do start ok direct to diesel if the starter motor is used. Maybe the OP's J2 would do the same.

 

 

[BEngo]

The J is much harder to start on diesel than the K, unless a thermostart/ hot air gun  is used.  The reason is that the combustion space is smaller so the heat of compression is quickly taken away by the cylinder walls and the air is not hot enough to ignite the diesel.

 

The no-petrol, direct starting versions had a really bad rep for hard starting when it was cold outside.

 

N

[BEngo]

Another tip.  Try setting the engine so no 2 is the first cylinder to fire before going through the priming routine.  This means you get two  consecutive firing strokes and the flywheel has more energy to carry the engine over the nect two idle strokes.

 

N

[Guest]

Thanks for the replies All.

 

I will give it another go after going through the process described by BEngo.

 

The engine is hand start and was always pig to start when cold.

 

I have some Champion K97F, but have rusted slightly, I will give them a clean up.

 

Regarding fuel, the petrol was fresh, but will change to E5, however, I did have some Aspen 2 and 4 which also did not work.

 

It wil be a week or so before I can get back to the boat to try again.

 

Thanks All.

[Tracy D'arth]

The only proper way to clean spark plugs is sand blasting.  Never ever use a steel or brass wire brush, they contaminate the insulator.

[BEngo]

Getting anything near the insulator on a K97F is  difficult at best.  The cente electrode is practically caged in by the outer three.

 

The two part spark plugs make life easier.  You can take then apart and clean them up nicely. ( Provided you don't drop the inner seal washer in the bilge).  I use a bit of green or maroon scotchbrite for the center electrode and a brass brush for the outer body.  I have two pairs of Lodge BL14, also with 3 electrodes and now in use since 1993 ish.  They need a clean about every 20 cold starts, but they are only working for 30 to 40 seconds at a go and 16 to 1 petrol mixture burns real mucky.

 

N

 

 

[bizzard]

On 11/04/2023 at 16:45, MtB said:

 

This is a classic rookie mistake. The most volatile fractions are added to petrol to make starting easy but they can evaporate away in as little as a month or two. Try it with newly-purchased petrol.

 

DAMHIK.

 

 

 

 

Why I only put £5 worth of petrol in my car at a time.

[BEngo]

45 minutes ago, bizzard said:

Why I only put £5 worth of petrol in my car at a time.

Is that even enough to wet the carburettor wick these days?

 

N

[MtB]

2 hours ago, bizzard said:

Why I only put £5 worth of petrol in my car at a time.

 

That won't get you far.

 

Probably about as far as pump No 7!

 

😅

[bizzard]

3 hours ago, MtB said:

 

That won't get you far.

 

Probably about as far as pump No 7!

 

😅

It'll get me just about 40 miles.

[Chris-B]

Late to the party but …when we got our J2 , Dick said to start on Aspen fuels as it doesn’t clog up 

works for us 

 

[Mike Adams]

Where did you get your replacement heads? I thought the supply had all but dried up. I would do a compression test to make sure you have some first. 

[MtB]

6 hours ago, Chris-B said:

Late to the party but …when we got our J2 , Dick said to start on Aspen fuels as it doesn’t clog up 

works for us 

 

 

Ok I'll ask.

 

What's "Aspen fuel"?!

 

 

 

 

[Mike Hurley]

https://aspenfuel.co.uk/products/aspen-fuel/

[koukouvagia]

On 11/04/2023 at 19:10, MtB said:

My K1 and K2 both now a pig to start on petrol. Maybe the change in petrol formulation is the reason.

 

They do start ok direct to diesel if the starter motor is used. Maybe the OP's J2 would do the same.

 

 

My K2 was always difficult to start on petrol despite K7F9 plugs and a reconditioned magneto.  I solved the problem by converting the magneto to a battery and coil start.  Worked perfectly every time.

[Guest]

On 01/06/2023 at 18:35, Mike Adams said:

Where did you get your replacement heads? I thought the supply had all but dried up. I would do a compression test to make sure you have some first. 

I bought an engine from a member on here, used what I needed and then sold the rest of the engine to the chaps on the south coast.

[Guest]

Engine now running. Condenser in the magneto was faulty. Had it replaced and now sparks well.

 

Engine is smooth and has seems to have good power. Not a lot of smoke either. Turned it around in the marina, gears all good.

 

Thanks all for the assistance.