Hydro-Lock!!!
 

Hello,

I was trying to start my H9 pts p51 yesterday and it didn't want to start i was using a new dubro spinner and prop and it seemed pretty snug to the fuselage compared to the stock 3 bladed spinner but i didnt think it would be a problem well i was using an electric starter so i didn't prime the engine at all and after about 3 minutes of trying to get her to start the engine totally locked. I can not move the prop whatsoever my question is how can i fix this if i can. I heard taking out the glow plug opening up the carb and try running the electric starter on it should work but i don't want to ruin my engine if i haven't already. Also if this is the correct method and it doesn't work am I SOL or are there other methods. Also what may have caused this could changing the spinner when its snug against the fuselage cause this?

Thank you for any help!

Brad

RE: Hydro-Lock!!!
 

Have you got the engine mounted inverted? If so, take the plug out, turn the plane upside down and gentle rotate the prop back and forth to relieve the fuel build-up. Then you can put the electric starter and and prop it with the plug still out.

RE: Hydro-Lock!!!
 

It is mounted at a 45 degree angle upwards.

RE: Hydro-Lock!!!
 

Hummm !!!! think my instructions for for an engine not-inverted . Just remove the plug and turn the prop over back and forth to get rid of fuel in the crankcase. Do this if inverted. Sorry

RE: Hydro-Lock!!!
 

Then remove the plug, tilt the plane until the head in pointing down and rock the prop back and forth by hand. Then try the electric starter.

RE: Hydro-Lock!!!
 

If it is Hydro Lock you will know right away when you remove the glow plug. It should turn very easy and running your electric starter for 10 seconds or so with the plug out won't hurt your engine at all, in fact it will help clear the excess fuel from the engine. Keep your face away from the engine it will spit out alot of fuel and it tastes terrible :eek:

RE: Hydro-Lock!!!
 

ok ill try this when i get back hopefully it works! Thanks

RE: Hydro-Lock!!!
 

Like Missileman said, just watch your eyes. Also, make sure you don't leave the glow plug washer sitting on top of the engine - it will get blown into the grass and lost.

RE: Hydro-Lock!!!
 

You said "the engine totally locked. I can not move the prop whatsoever". Even with the engine hydro-locked it should move some even if backward. If it won't move at all, it is siezed or binding on something.

So first question is: Will it actually not move AT ALL?

RE: Hydro-Lock!!!
 

Good question. Did you remove the PTS flywheel? Is the prop somehow rubbing against the engine so that it cannot turn?

RE: Hydro-Lock!!!
 

The engine WONT move at all. I have no idea what it could be rubbing on for some reason when i changed the spinner it is all tight and when i tried to start the engine the prop wasn't moving as freely as it did with the other spinner i assumed (very stupid of me) that it wasn't a big deal but now this has happened so I guess it was a big deal.

RE: Hydro-Lock!!!
 

Did you alter or remove the drive hub (flywheel attached) or any other parts behind the spinner?

Have you tried it without a spinner at all to see if it will move?

RE: Hydro-Lock!!!
 

BTW - you do NOT have a hydro-lock.

RE: Hydro-Lock!!!
 

It's been a while, so my memory is hazy, but I think that when I switched to a 2 blade prop on my Alpha 40, I needed to leave the flywheel on for it to work. I think that without the flywheel, there was some binding between the prop and the crankcase.

You should take off the new prop and see if the engine turns freely.

RE: Hydro-Lock!!!
 

If I recall properly there is a small washer behind the drive hub that keeps the drive hub from touching the engine casing. If that washer is missing there WILL be metal-to-metal galling and a likely seizure.

RE: Hydro-Lock!!!
 

So if I lost that washer and it has seized up is there any way of fixing this or have I just trashed the engine?

RE: Hydro-Lock!!!
 

You should have been able to press the flywheel off of the drive hub and been OK. The only way for the prop to contact the case is for the hub/flywheel to be missing.

RE: Hydro-Lock!!!
 

Assuming I am right about the washer - it needs to be replaced and then you should be OK. I'm gonna hunt for a part picture to check.

RE: Hydro-Lock!!!
 

It may be the new spinner. Is it a platic one?
Some of the plastic spinners recess back behind the prop hub because of blind nuts molded in. It may be catching on the front of your cowl. If this is the case the best solution is to get a spinner that doesn't recess. Aluminum spinners and the plastic spinners with aluminum backplates will work, there are some all plastic spinners also that don't have a recessed area but I can't name one off hand.
As Bruce suggested, remove the spinner and prop and see if the engine will turn.

RE: Hydro-Lock!!!
 

http://h1071118.hobbyshopnow.com/Pro...X_Exploded.pdf

item #10 on this drawing is the washer I'm referring to.
Item #18 is the flywheel/hub and item #9 is the non-flywheel driver hub that is available.

RE: Hydro-Lock!!!
 

ok I know for a fact that the spinner has a recessed back I will remove it tonight when I get home.

RE: Hydro-Lock!!!
 

I know i have the flywheel but i also know the flywheel has fallen off a couple times I bet that I am missing the washer.....

RE: Hydro-Lock!!!
 

Oops, that's easy to do. Without it the back of the drive hub will grind into the case. No serious damage though.

RE: Hydro-Lock!!!
 

In case you do not want to try to remove the flywheel, you can also purchase a prop hub as a part w/o the flywheel.

That way you can switch them at any time if you desire.

RE: Hydro-Lock!!!
 

No prime, no fuel, 3 minutes of winding over dry...it's possible you've seized the piston in the liner. I once watched someone winding an engine over like that and he seized the crankshaft in the crankcase (plain bearing engine). Electric starters can kill an engine very quickly if used incorrectly.