Starting a car that has been sat for years

[TommyC]

I’ve just picked up a losi 5t. It’s 8 years old and has apparently been sat for 5-6 years. I got it for a good price and expected there might be some issues but it’s generally a clean car with very little wear and tear.

 

I’ve put a dumboRC rx in there but don’t currently have the correct battery connector. Funnily enough I’d already ordered some for something else and hopefully they’ll turn up tomorrow.

 

put some fuel in and found the return hose had split so we sorted that out. Then found the spark plug gap needed closing up but it still wouldn’t start. Compression seems ok.

 

I’ve not owned a petrol RC for over 10 years and don’t remember much about it so just wondered if I was missing something obvious? If not obvious, where should I start looking?

 

[locky]

Does it have a kill switch? Fuel getting to piston? Spark at plug? Strip the carb and clean, as possible dried fuel residue.

[markymarky]

Looked back at the for sale thread for this and noticed something a bit odd.

There is a filter in what is the fuel return line, people think the clear tube is the fuel in cause that leads to where the primer bulb is but it is in fact the return.

I am wondering if the lines are connected in the right place, the black tube is the fuel in and pushes onto the carb underneath, the clear pipe is the return that is near the primer bulb.

Also not sure why there would be a filter on the fuel return line and if it is still there it might be blocked and could be causing an issue , also as well as being on the wrong fuel line it might also be the wrong way around?

Not sure it would have any effect though but worth checking if the lines are connected correctly if nothing else.

Edited May 20 by markymarky

[TommyC]

We noticed the black is fuel in as it has a filter on the end at the bottom of the fuel tank. Wasn’t sure what the little thing on the return was but we noticed the return had split where it goes through the bung because it was leaking when trying to start. So maybe that filter isn’t blocked but do you think I could just remove it?

 

I have fully stripped one and rebuilt one of these engines and carbs years ago. Just need to remind myself how to do it again!

 

would be nice to get it running but ultimately I want to go electric with it. Got a lot of other stuff on my plate at the moment so this might not get too much attention for a while.

Edited May 20 by TommyC

[markymarky]

You could just remove it, its not really needed. 

It could be possible the filter in the tank that is blocked, it might have just degraded with time. 

Also i have found in the past it is worth making sure the air filter is clean, it could just be choked with dust where it has been sat or again maybe just degraded with time. 

Have you checked it is actually sparking at the plug, remove the plug with the lead attached and touch it to the engine, pull the starter and see if the plug sparks. 

 

Edited May 20 by markymarky

[TommyC]

The carb primed within seconds and both fuel and air filter looked clean. We did try with the air filter off. Checked spark and that’s when I noticed it was off as was shorting. Set gap to .040 and spark was improved. 

[wolfie1]

Take the pull start and the metal shroud off and behind it is the stator coil which produces the spark, any rust on the metal pickup will give you a really poor spark, clean it up with a bit of sandpaper 

[markymarky]

2 minutes ago, wolfie1 said:

Take the pull start and the metal shroud off and behind it is the stator coil which produces the spark, any rust on the metal pickup will give you a really poor spark, clean it up with a bit of sandpaper 

 Would have been my next suggestion.

Just cause a plug sparks doesn't mean it is sparking as much as it could.

[TommyC]

I did think the spark looked poor and was trying to remember how it creates the spark. Will have a look tomorrow now. 

[TommyC]

Quick one on the battery. The dumborc receiver says it will take 4-10V. Can I fit a LiPo in there? Only I’ve got plenty laying around. Will the savox servos be able to take a range of voltage and LiPo power?

[TommyC]

Right. I’ve rebuilt the carb. New spark plug too. Primes ok but just doesn’t seem to put any fuel through. Does this mean the compression is insufficient to generate a pulse for the carb?

 

I figured out the servos can take 7.4v but apparently standard servo connectors are not suitable for Lipo power? Will it be ok because of the minimal draw of a servo compared to an electric motor?

Edited May 31 by TommyC

[TommyC]

Ok. After lots of tinkering I have come to the conclusion the compression is not good enough. So I wanted to start with just putting a new ring on but I can’t seem to find them anywhere. Where can I get spares for a cy260 engine?

[bombercountynick]

Check the gap from the flywheel to the coil, also well worth cleaning it up if it's been stood for a while.

 

Is it getting spark?  check to see if it's getting spark just pull the plug, pop it back in the HT lead and earth it against the top of the cylinder👍

[TommyC]

Spark is just fine. Carb is letting fuel through. Thought compression was ok but actually when you have the cover off and just turn the flywheel it’s too easy and not making the pop noise it should. I’ve had it all apart and it all looks good.

 

Ive been looking all over and it seems really quite difficult and/or expensive to get parts for the 2 bolt engines. Especially pistons and heads. I can get a gasket set and piston ring for around £20. But I also need an isolator block and ideally flywheel cover as I snapped a bolt in it. It just doesn’t seem worth putting money into an engine that is going to be difficult to maintain and more difficult to upgrade.
 

also, rcmodelz list a 34mm x 1mm ring as not suitable for the cy as the groove is smaller (I think I read 0.7mm somewhere). But I do have a 1mm ring so if the above is correct then I think maybe the last owner put a new piston in there?

 

My brain is telling me to buy a new engine but my heart really wants to get this going as it’s such a clean car and there doesn’t look like there’s anything particular wrong with engine either.

 

I’m also considering brushless although the never ending run time of gas does appeal to me. Circa £300 for a g320 would go a long way towards a conversion. 

Edited June 3 by TommyC

[TommyC]

IT’S ALIVE!!

 

new piston ring and gasket seems to have done the trick. Started after 2 or 3 pulls and died off then stayed on with the next pull. Need to tweak it and I’m not sure the clutch is engaging early enough but I’m just proper chuffed to get the engine going. Only £340 into this 5T so far.

[tersch]

Hello TommyC.

I'm having the same issues as you had regarding starting my 5T after a few years of non action.

I have pretty much done everything I thought possible to get the thing going again but still nothing!

Interested to know what you eventually did to get yours going?

Was it a reduction on the spark plug gap? I believe 0.6 to 0.7 from the manual? You mentioned 0.4? 

And also the piston ring... Can you confirm the new ring did the trick? I have a CY 28-36.

I have done the following: - fresh fuel, new head gasket, new fuel lines, new spark plug, new carb gaskets, (carb seems clean) new air filter (previous one had a rip in the foam), ignition coil contact to flywheel is clean with business card gap set. fuel flows fine. I have a spark from the plug and removing the plug and placing thumb on top of cylinder seems to give compression by feel. Although i'm no expert on how strong that compression should be (hence possible piston ring replacement?) Its not flooded as I've turned upside down and and cranked... It just does not fire at all. Frustrating.

Any help would be appreciated.

Thank you.

[TommyC]

For me it was the piston ring that did the trick. I did change all the gaskets at the same time so that may have been part of the problem.

 

Basically I started off on the wrong foot thinking the compression was good when it wasn’t. It should make a nice pop sound with each turn. Also the 0.4 spark gap was incorrect. I put a new CMR7H spark plug in and set at 0.65. I rebuilt the carb but tbh as I was pulling it apart I didn’t feel it was necessary. I too checked the coil gap, fuel lines, air filter, gaskets etc. Only when I did the piston ring it became obvious that was the problem all along.

 

I got the ring from here

https://www.rcmodelz.co.uk/34mm-26cc-piston-ring.html

 

It does say it’s too thick but as I said before, my engine already had a piston with a 1mm thick ring. Best thing to do is pull yours out and measure it.

[Ziggy122]

On 20/05/2024 at 20:18, TommyC said:

I’ve just picked up a losi 5t. It’s 8 years old and has apparently been sat for 5-6 years. I got it for a good price and expected there might be some issues but it’s generally a clean car with very little wear and tear.

 

I’ve put a dumboRC rx in there but don’t currently have the correct battery connector. Funnily enough I’d already ordered some for something else and hopefully they’ll turn up tomorrow.

 

put some fuel in and found the return hose had split so we sorted that out. Then found the spark plug gap needed closing up but it still wouldn’t start. Compression seems ok.

 

I’ve not owned a petrol RC for over 10 years and don’t remember much about it so just wondered if I was missing something obvious? If not obvious, where should I start looking?

 

okay this based on a little bit of work I did on a strimmer....

 

Have you got a spark? earth it on the head and pull your cord

No spark = kaboom

 

Been sat - the fuel needles Will likely be gummed up, petrol varnishes overtime

it could have a full fuel bowl but isn't actually spraying into the venturi 

He'll the fuel bowl could be gummed shut = no fuel....

 

I'd suggest a cheap can of carb cleaner - take the carb off and just go to town on it

 

then let it dry and then refuel and retry

[tersch]

O.k. great. Thanks both for your prompt replies.

I'll check the ring tomorrow and order a new one. It's probably the only thing I haven't done ! I've almost built a new car as it is !

Yes I do have a spark. I have a 'killer' switch on it and that is working. Wasn't sure how strong the 'spark' should be but figured a spark is a spark. If the coil was knackered it wouldn't spark at all.

I do a have a new can of carb cleaner specifically for this, so will take off and give it a good blast.

Thanks again. I'll report back.

Kind regards.

[TommyC]

I could tell the carb was working properly as I’d take it off and dry the inlet port, try it, take it off again and have traces of petrol in the inlet port.

 

mine apparently hadn’t been run for years but the carb was perfectly clean. Apparently if you’re storing the car for long you’re supposed to let the carb run dry.

[tersch]

Yes. After having an arm like Schwarzenegger, the sound of the piston just seemed 'dry'. There's no wet plop sound that I remember on past starts. I.e. no fuel.

I've read elsewhere that chocking isn't favorable... Personally I always have. Makes sense running the carb dry pre-storage. I'll be sure to do that next time.

Fingers crossed there will be a next time.

[tersch]

Success! It was the piston ring. No choke, better plop noise on cranking and half a tin of carb cleaner! 😁 6 pulls and she fired. What a glorious noise. 

Thanks for your help. 👍