Nitro engine - fault diagnosis please

[OfnaHyper]

Hey there guys

Could someone explain the problem I have with my engine please.
When I go to start my engine the rotostart is finding it very difficult to turn over. I can loosen the glow plug slightly and it will turn over nicely but will not start prob because I'm losing the compression. Its even harder to turn over when I have primed it. I'm tempted to put the pullstart back on and see if that will help.
The engine is a HPI F4.1 out of a savage. Its not in a savage its in a hong nor truggy.

Thanks in advance.
Any help or feedback much appreciated.

 

[Metalhead Matt]

Preheating the engine with a hairdryer helps to loosen them up. Is your engine new?

 

[OfnaHyper]

Preheating the engine with a hairdryer helps to loosen them up. Is your engine new?

hey matt. its far from new now. prob had atleast 1-2 gallons through it. It was fine last year. The weather is improving now so dragged all the gear out and fancied a go. But this is what starting happening pretty much straight away.
Cheers.

 

[MotoGod]

If it's got 1-2 gallons through it...sounds like you may be flooding it. If you pull the plug out completely....does the RotoStart spin it freely? Does it start out hard to spin....or get harder as you try more? Assuming your battery is not weak in the RotoStart that is....the pullstart won't be much better. RotoStart spins pretty good when it's fully charged and working correctly.

 

[OfnaHyper]

If it's got 1-2 gallons through it...sounds like you may be flooding it. If you pull the plug out completely....does the RotoStart spin it freely? Does it start out hard to spin....or get harder as you try more? Assuming your battery is not weak in the RotoStart that is....the pullstart won't be much better. RotoStart spins pretty good when it's fully charged and working correctly.

I charged up all batteries last night ready for today.
What I have been doing is putting the rotostart on with no glow plug and a bit of after run oil just to get it lubricated slightly. It spins it perfect, nice and fast. Then I put the glow plug in and gradually tighten it whilst spinning the rotostart. When the plug gets to almost fully tight the rotostart will lock and get hot as its struggling to turn the engine over. If I loosen the plug by 1/4 turn it turns over again. This is with not priming the engine.

 

[MotoGod]

No need for after run oil to lubricate it up. That's meant for "after a run" ;-) That is probably locking up your engine when you try and start it. Too much fluid in there. Pull the plug out. Spin the engine over for a few seconds to clear out the oil/fuel mixture. Then let it sit for a few minutes, re-prime it ad try again.

 

[OfnaHyper]

No need for after run oil to lubricate it up. That's meant for "after a run" ;-) That is probably locking up your engine when you try and start it. Too much fluid in there. Pull the plug out. Spin the engine over for a few seconds to clear out the oil/fuel mixture. Then let it sit for a few minutes, re-prime it ad try again.

its been sat for a few months thats all and the after run was the only oil i had to lube it. turned it over a few times after this and dropped a bit of fuel in to help it a bit more. The thing is when i have taken the plug out i have turned it over with the rotostart to get all the excess fuel/oil out. I am going to heat it up at home next see if that will help. Not sure how I am going to do this out at the track tho.

 

[Rolex]

You shouldn't have any trouble getting it started by loosening the plug. You need to take it out, put the ignitor on it and see what kind of a glow you're getting.

 

[Metalhead Matt]

What batteries are you using in the roto start?

 

[OfnaHyper]

What batteries are you using in the roto start?

it is a 2500mAh 7.2V extreme power racing 6cell stick battery. It doesn't have a problem turning over my other F4.1. As for the glow plug it seems ok. nice and bright.

 

[Rolex]

Take off the air cleaner and put some fuel directly into the carb. If it starts then stalls, you have a tuning issue or a clogged needle.

 

[w bill]

Maybe rotostart motor is going bad check all your wires and conections.