Johnson 3.3 hp starting problem

[Lubosleftboot]

Hi Guys,

Looking for a bit of advice on trouble getting this engine to start. It is a single cylinder 1998 model with straight drive.

When I acquired the engine the spark was very weak and eventually died so I replaced the power pack and now there is a bright blue spark present. As the engine was sitting a while (18 months) I stripped and cleaned the carburettor and all is well concerning that in that the float and needle are both in good order and the jets are clear and free from gunk.

As per another post on here I have checked the compression 50psi ( is this high enough?) And I have removed the flywheel to check that the woodruff key is intact which it is and therefore timing aint the issue.

If I spray starter aerosol into the spark plug hole the engine will fire a couple of times but it wont start...I am suspecting either gummed rings from sitting about or perhaps the fuel has gone off..

All advice is appreciated guys...

LLB

 

[kenmyfam]

Re: Johnson 3.3 hp starting problem

Dump the fuel, clean the carb again and fuel lines and never, never spray starter fluid into a 2 stroke. Use a spray bottle with the correct mix of 2 stroke oil and fuel.
Good Luck.
just my 2 cents

 

[kenmyfam]

Re: Johnson 3.3 hp starting problem

No harm in giving it a decarb either once you get it going.

 

[Vic.S]

Re: Johnson 3.3 hp starting problem

50 psi is very low

starting fluid is bad for it ... no oil ... but if it wont start when using it then somethings wrong.

Stale fuel is bad news and if really bad will just about prevent it from starting

If you have a good spark and you are sure you have cleaned the carb well chuck out the old fuel and mix fresh (50:1 ). Try also a small squirt of oil onto the piston top to seal around the rings.

Choke closing OK ?

Plug Ok? L87YC or QL87YC gapped 0.030". Tried a new one?

Fuel getting to carb OK?

 

[Lubosleftboot]

Re: Johnson 3.3 hp starting problem

I have tried a new plug as well and it is gapped OK so I will start with flushing the fuel system and going from there..I will post back on this thread to let you know if this sorts the problem out.

TY for the advice guys

LLB

 

[Lubosleftboot]

Re: Johnson 3.3 hp starting problem

Right guys I have done as you suggested in that I have put 2 stroke oil in the bore to seal the rings and have put in new 50:1 mix in the petrol tank and still no joy.

I have noticed though if I put some 50:1 mix direct into the cylinder the engine will fire a couple of times producing smoke but the sod still wont start..

Where do I go from here..the carb seems clean enough and I can see through the jets....is there anything else I can try before putting this motor in the trash?

TY for your help in this matter it is truly appreciated.

LLB

 

[bktheking]

Re: Johnson 3.3 hp starting problem

Did you test compression after wards? If it's got a blown head gasket there will be no joy. Sounds like it, test comp and if its still low pull the head and inspect.

 

[Lubosleftboot]

Re: Johnson 3.3 hp starting problem

Did you test compression after wards? If it's got a blown head gasket there will be no joy. Sounds like it, test comp and if its still low pull the head and inspect.

TY BktheKing...I will do that tomorrow mate

 

[1946Zephyr]

Re: Johnson 3.3 hp starting problem

It should still run with 50psi, but that is kind of low. I have a 58 3hp that delivers 60 psi on each cylinder and those pistons are smaller than yours. Once you get it to run for about an hour or so, try the compression again. I have often found things get better after running and fresh mix gets in around the rings and cleans things out a bit. It may need a decarb too.

Check over the ignition system good and make sure all contacts are clean and rust free. The spring connection under the spark plug boot will sometimes lose contact, due to rust. I'm sure your motor is electronic ignition, but I would still check things over and make sure everything is clean.