Hot starts

[The-sky-captain]

Mooniacs- How long after shutdown does a hot start still need to be done IYO? I'm still working on perfecting my method being that it still gives me problems about 10% of the time:) Any tips...

[mooniac58]

Good question, I would like to hear more on this too.  Generally my own rule is to try a hot start if it has only been 1-3 hours since the engine was running.  If it won't start quickly I generally prime it again and do the cold starting method.  Then again I live where it is normally 75-85 degrees outside and the engine probably cools slower than a cold winter day, etc.

[TurboExec]

Anything longer than about 2 hours and I do a cold start....

[The-sky-captain]

You just have to rub in all the good wx you get don't you:)

[eaglebkh]

I've had success using the following technique - it's a modification of one I found posted somewhere else regarding Mooney hot starts.

If you know you're going to be starting the engine shortly after shutdown, then leave the engine at 1000rpm when shutting off. Don't touch the throttle again until after you have it started again. For engine starts within the next half hour, it should fire right back up without any priming. Beyond that, I usually prime 1 second per 30 miuntes of down time up to 5 seconds. For example, if the plane sets for 1.5 hours, I would prime for 2 seconds (1 second of prime for every 30 minuntes of downtime beyond the initial 30 minutes).

It's complicated, but it works. I often find myself not doing "hot" or "cold" starts - usually somewhere in between.

[Mooneyland]

With all of the Mooney's that I get to fly, each one is a bit different, but this is what I do on average for what it's worth:

http://www.mooneyland.com/Starting_a_Mooney.htm

I gave the web page in order to not have to re-type the information here. I hope this helps some.

 

Fly safe,

Richard Zephro Mooneyland

[Mooneyland]

Unless it's freezing outside, I personally do a hot start unless the plane has sat 4 hours or more. The thing is with a hot start is that if the plane has cooled off too much for the hot start; you haven't hurt anything whereas if you do a cold start on a previously started engine; you may have to do the flooded start thing and no matter what, I think that the engine does not like you when you have to do that. I would always try the hot start first before going to the cold start proceedure.

If your Lycoming doesn't have the newer light-weight high speed starter by Sky Tech, save your penny's and get one! The engine turns about twice as fast during starts and makes all the difference in hot starting those injected Lycomings.

Fly safe,

richard zephro; Mooneyland.com

[eaglebkh]

Richard,

I have the Sky Tech starter and the procedure I use for normal starts in my E is very similar to your procedure for the turbo 6-cyl engine.  I guess the starter makes the difference.

[Mooneyland]

I'm not completely sure if that is the starter or the engine. This is a fleeting subject for the norm because every Lyc seems different just like every Mooney is a bit different being hand built. Some are so easy to start that I have done the usual thing and they wanted cold start even when warm. Go figure. Others are as difficult to turn on as an ex wife, but one thing that I do know is that the method I use universaly normally gets 'em started no matter the mood. The more you get to know your own airplane, the better and easier it is to hot start because you learn the idiosyncrocies.

Here's the greatest thing in the world............You own your own Mooney's! What a priviledge!

Fly safe,

richard zephro Mooneyland

[mooniac58]

I recently upgraded my '87 M20J with a new lightweight Skytech and what a difference!  I never crank that baby more than 3 seconds hot or cold and poof - she just starts!  Worth every cent.

[Mooneyland]

I'm happy you posted that information because the Sky Tech starter is an amazing add-on that warrents acknowledgement. It is just that much better of a starter than the OEM starter. For about $300 and something, it is one of the most single things you can do to improve the system and I'll tell you what; I think because the Sky Tech does such a better job that it will pay for itself in ways unimaginable, makes the engine run better and last longer due to the limit of abuse these engines go through. More than 80% of engine wear is at the starting of the engine and the easier it starts the easier it is on your engine. Let's face it. Engines are a substantial part of the cost of operation and anything you can do makes it last longer and yields CHEAPER OPERATING COSTS!

Just my 2 cents worth.

Fly safe,

richard "zef" zephro Mooneyland.com

[Lood]

I hope someone can help me out here on Skytec starters. I read somewhere that certain models are more durable than others and these are identifiable buy a specific letter following it's model or serial number. I've been trying to find that post, but unfortunately I have'nt been successfull thus far.

I have a Skytec starter on hand that I want to have installed with the next annual, but I want to be sure it's the better one - just can't remember which letter indicates that?

[The-sky-captain]

On another note. This morning when I started my plane I heard it backfire. This has never happened before. Any suggestions?

[fantom]

Quote: The-sky-captain

On another note. This morning when I started my plane I heard it backfire. This has never happened before. Any suggestions?

[Mooneyland]

Checking your muffler is sound advice. Busted pieces of the internal baffles can kill an engine if the pieces block the exhaust.

Backfires happen sometimes when too much fuel is collected in the cylinder and when a spark goes off kaboom.

Check that muffler.

richard @ mooneyland

[Jeff_S]

This thread has sat idle for 9 months so I thought I'd reactivate it to see if there are any other experiences out there people want to share. I'm still getting used to the whole fuel-injected "cold start vs hot start" technique and as summer approaches and I expect to fly more multi-leg trips, the hot or warm-start technique will be important.

So far, I'm just following POH instructions on hot start, which is mixture at cut-off, throttle in just until the "click" of the gear warning horn activater, crank her up.  This has worked 8 out of 8 times, but it does seem to crank for about 10-15 seconds before catching. I may experiment with the technique described above, giving 1 second of boost for each 30 minutes of rest. And yes, a SkyTech starter is on the list for eventual improvements but all things in time!

[scottfromiowa]

I have never done the (regarding hot start procedure) turn on boost pump 2-3 seconds with mixture at cut-off..(to pressureize the fuel) this makes some sense.  I have been quick with mixture, but have NOT fluttered the throttle...I will give this technique a try...I have had success...and frustration with the leave it alone and crank...then mixture for hot start.  Thanks for the link to the article.

[flight2000]

I have a Sky-Tec starter installed and when I'm shutting down after a flight will pull the throttle back to 1000 RPM and then cut the mixture.  I DO NOT touch anything when starting the engine after refueling (or whatever else I was doing) except the ignition key and it normally starts after about 3 blades.  No fuel pump, mixture in/out, etc.  Mine starts faster warm than cold, go figure.

I have a checklist I use posted on my website in the manuals section.

Brian

[fantom]

Question for your Sky-Tec M20J guys:

Do you have the the 149 NL 9.4 lb unit that spins very fast, is good for 60 seconds, and has a 12v motor that also converts to 24v, or...

Do you have the newer (?) 149 NL-ec starter, 8.5 lbs, Super Duty unit that's only a 24V motor, not as fast spinning, but can outlast the battery; up to 6 minutes?

Interesting comparison, if and when the ol' Prestolite gives up the ghost. 

[tablor]

Here's the starting rules I use from Dave McGee.  He flies lots of different Mooney's and these procedures have always served me well.

http://www.mooneypilots.com/mapalog/HOT%20STARTS.htm

I can't find it now, but someone commented that they like to run the pump with the mixture at cutoff to pressurize the system and then further down the thread (perhaps a different thread on starting which is why I can't find it now) someone else said that doesn't help for a Lycoming only for a continental.  Anyone know why that would be true?  Boost pump does provide vapor suppression - I think that's why it's in the checklist for descent, to prevent vapor buildup that could occur.  Isn't that what makes hot starts a challenge, hot engine causes fuel lines to contain too much fuel vapor and not enough fuel?  It seems like the last bit of fuel line on top of the engine would be the most difficult place to be sure there was fuel - IE that's the highest point in the system.  Dave's procedure doesn't say anything about boost pump for hot starts, but I'm using the boost pump on every start.  Is there a reason that having the boost pump on wouldn't be desireable?

Maybe it's dumb for me to think about this as I often make fuel stops and have to hot start but have never had a problem, just thinking out loud, it's early.