bravo hard starting

[toomany]

been having issues w the bravo starts lately. i used to prime for about 8 seconds and it would fire after several rotations on full rich, 1/2 -1" throttle.  it seems to have been getting consistently worse over time.  today i tried the j starting tip i read here - full rich, open fuel servo and prime for 20 seconds. it wouldnt fire even after waiting several min (10) for fuel to eveaporate. i got out and noticed a rather large puddle of fuel under sniffle hoses - so i pished it back and rocked it back and forth to try to get more fuel out of the intake belly. i got a pretty steady trickle for about 1.5 min while rocking.(like an 80 year old w a prostate issue). tried again w mix shut and fuel servo 1/2 way in and still nada. ended up pushing back in the hangar w a dead #2 and low #1 battery.  obviously the texhnique didnt work. ive tried heavy prime rich and lean, open closed throttle  , no prime same way, a little prime etc etx. im thinking ive got mag issues but just had them redone less than 200 hrs ago. 

oat was 38°F and engine was warmed via block heater since flying it yesterday.  

yesterdays start was best in a long time w 15 seconds of prime, mix rich and throttle 1/4". stopped and got fuel after an hr of flying and hard started again almost leaving me stranded in the poconos. 

any input, suggestions, tried and true bravo start routines are greatly appreciated. 

fyi- on pre-buy the key switch was fixed as it would only fire after you left off the start position.  it seems to still do that intermittently, but yesterday after the fuel stop it finaly started by popping intermittently until it got through all the fuel - key was in start position the entire time

[Rmnpilot]

Are you able to confirm that you have sufficient fuel pressure?  It sounds like it given you having a puddle of fuel outside the plane.  I cannot think of any time I’ve ever used more than 6 seconds of boost and I’m based in the upper Midwest.    My gut says you may be priming too much at the length of time you're using.  Look at the POH and understand that if you’re using a preheater you can probably go much less on the boost pump given the engine is at a higher temp (not 30s).    
 

[Fritz1]

I typically prime 4-5 sec with the throttle with mixture full rich, close throttle and open 1.5 turns, fires after 1-2 revolutions, i rather underprime than overprime, if underprimed, give it another one second shot and she will fire, have slick start mag booster, check your mag timing, clean plugs

[toomany]

fuel pressure is good and stabilizes around 40psi very quickly on boost(1-2 seconds). plugs are fine wires and exhibit no misses on mag checks - dame for mags.  

anyone have feedback on electronic ignition on the bravo.  thinking that may be next step regardless, as im not a big fan of using 1940's technology w alot of moving parts - at least w one electronic ignition "magneto" there may be a little more assurance that timing won't drift w wear.  if anyone is using an electronic mag can you tell me if yiu can replace the mag w the impulse coupling or is it the other that gets swapped out?

[PilotX]

Don't forget the chart.

 

[Fritz1]

Try the slick mag booster on the impulse coupling mag, the real problem with the impulse coupling is hot starts, the skytec starter turns the engine so fast that the impulse coupling does not engage, engine fires when you let off the starter. I have a retard breaker mag on the shelf that is a legal replacement for the impulse coupling mag, this combination will hopefully fire like gangbusters. I had an electroair ignition and removed it for many reasons. If interested in an in depth discussion PM me. I know where you are coming from, have been there.

[Danb]

18 hours ago, toomany said:

fuel pressure is good and stabilizes around 40psi very quickly on boost(1-2 seconds). plugs are fine wires and exhibit no misses on mag checks - dame for mags.  

anyone have feedback on electronic ignition on the bravo.  thinking that may be next step regardless, as im not a big fan of using 1940's technology w alot of moving parts - at least w one electronic ignition "magneto" there may be a little more assurance that timing won't drift w wear.  if anyone is using an electronic mag can you tell me if yiu can replace the mag w the impulse coupling or is it the other that gets swapped out?

When I had my Bravo I installed the surefly electronic ignition which helped quite a bit on it. I also installed a surefly on my acclaim which helped a little. I’m of the belief there well worth the investment 

D

[LANCECASPER]

20 hours ago, toomany said:

fuel pressure is good and stabilizes around 40psi very quickly on boost(1-2 seconds). plugs are fine wires and exhibit no misses on mag checks - dame for mags.  

anyone have feedback on electronic ignition on the bravo.  thinking that may be next step regardless, as im not a big fan of using 1940's technology w alot of moving parts - at least w one electronic ignition "magneto" there may be a little more assurance that timing won't drift w wear.  if anyone is using an electronic mag can you tell me if yiu can replace the mag w the impulse coupling or is it the other that gets swapped out?

You mentioned in your first post that it used to start fine, and now it doesn't. I wouldn't put any add-on contraptions on the airplane until you find out what the underlying problem is.

If it has plenty of fuel, and there's no air restriction and you've pulled your plugs to see that they look good and have low resistance (fuel, air and spark), about the only things I can think of are (1) the timing (when it sparks) and (2) testing that your ignition harness is good and letting the electricity get to the plugs.

[toomany]

Everything checks out as far as electrical and fuel. I said it seems to have gotten worse over time but that may have been a result of my diverging from normal starting ops in my search to find the magic start sequence. Today i primed it for 6 seconds and began spinning it - after about 5 - 8 seconds of cranking, it started popping on a cylinder or two. I continued cranking for another 20 or so seconds and when i couldn't stand the abuse to my starter anymore I let go of the key amd as soon as i did it fired up. This has happened several times since ownership and today i remembered a squawk in the pre-buy that there was an issue w the ignition switch thay caused this very issue. Im going to touch base w the mooney svc center that did the prebuy to see if they recall the remedy during the prebuy.

After it started today I flew it for 2 hrs., stopped for fuel and left the cowl flaps closed, oat was in low to mid 60's. At restart I didn't prime at all, just pushed the throttle in to full open w no elect power on (boost didnt activate) and then set it at about 1/2" open - it fired right up.
I will continue to use the same procedures i did today and at the same time try to get an explanation on why it fires up cold only after you let go of the key. Ill update as i find, or if i find a solution. Anyone w similar experience or more knowledge than me on this please add your 2 cents.
Hope you all have a Merry CHRISTmas.


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[LANCECASPER]

10 hours ago, toomany said:

Everything checks out as far as electrical and fuel. I said it seems to have gotten worse over time but that may have been a result of my diverging from normal starting ops in my search to find the magic start sequence. Today i primed it for 6 seconds and began spinning it - after about 5 - 8 seconds of cranking, it started popping on a cylinder or two. I continued cranking for another 20 or so seconds and when i couldn't stand the abuse to my starter anymore I let go of the key amd as soon as i did it fired up. This has happened several times since ownership and today i remembered a squawk in the pre-buy that there was an issue w the ignition switch thay caused this very issue. Im going to touch base w the mooney svc center that did the prebuy to see if they recall the remedy during the prebuy.

After it started today I flew it for 2 hrs., stopped for fuel and left the cowl flaps closed, oat was in low to mid 60's. At restart I didn't prime at all, just pushed the throttle in to full open w no elect power on (boost didnt activate) and then set it at about 1/2" open - it fired right up.
I will continue to use the same procedures i did today and at the same time try to get an explanation on why it fires up cold only after you let go of the key. Ill update as i find, or if i find a solution. Anyone w similar experience or more knowledge than me on this please add your 2 cents.

If it ends up being your switch, rather than replacing it with another AD-prone Bendix switch, this is a good alternative: https://www.aircraftspruce.com/catalog/elpages/ea_08-17141.php

When doing a new panel on the last Bravo I owned I put one in and was satisfied.

[toomany]

thank you Lance. I prefer the two rocker switch and push button design over a key, that if you have a second key or a keychain attached to it, dangles too close (im my opinion) to your left knee when full fwd in the seat. one question - does this switch replace a keyed ignition completely? I imagine it does and would prefer only having 1 key for the baggage cockpit doors.


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[LANCECASPER]

47 minutes ago, toomany said:

thank you Lance. I prefer the two rocker switch and push button design over a key, that if you have a second key or a keychain attached to it, dangles too close (im my opinion) to your left knee when full fwd in the seat. one question - does this switch replace a keyed ignition completely? I imagine it does and would prefer only having 1 key for the baggage cockpit doors.

Yes it does, leaving one key for the baggage and cockpit doors. The only thing to add to the checklists is either to turn on (start) or turn off the mag switches (shut down). It’s also eliminates getting buckled in and the seat adjusted just right and then realizing that the ignition key is still buried  in your pocket.

[toomany]

thank you Lance. i think ill add it regardless just for the convenience - keys and i are like oil amd water. thank you.


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[Pinecone]

The firing as you release the key from start is a known issue.

It indicates a failing left mag.

 

 

 

[toomany]

thanks pinecone - im leaning more toward an ignition switch, or a grounding issue on the left mag and and will check both asap and update here. i can hear the impulse coupling clacking on start up but that doesnt mean its doing its job if grounding is affecting it. whats puzzling is that sometimes it starts right away when its warm but other times not. Lately cold starts only happen w exact prime and key release.


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[skykrawler]

Sounds like magneto.   How many hours on those magnetos?

[toomany]

150, maybe 200hrs. interestingly first set of mags that were redone at overhaul went out about 100hrs in. im now wondering if there is an intermittent short from the ignition switch that may be causing a fault in the impulse coupling. im going to replace the ignition switch w mag rocker switches and a push button start first to see what happens. when i remove ignition switch ill ohm out the p-leads and check for continuity based on switch position. regardless, getting rid of the ignition switch will be a net positive even if condition persists.


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[LANCECASPER]

4 hours ago, toomany said:

150, maybe 200hrs. interestingly first set of mags that were redone at overhaul went out about 100hrs in. im now wondering if there is an intermittent short from the ignition switch that may be causing a fault in the impulse coupling. im going to replace the ignition switch w mag rocker switches and a push button start first to see what happens. when i remove ignition switch ill ohm out the p-leads and check for continuity based on switch position. regardless, getting rid of the ignition switch will be a net positive even if condition persists.

Who did the overhaul on this set of mags?

[toomany]

local a&p at the field did the OH on the set thats on the bird now, first set was done by Columbia in bloomsburg PA where engine was done.


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[LANCECASPER]

7 minutes ago, toomany said:

local a&p at the field did the OH on the set thats on the bird now, first set was done by Columbia in bloomsburg PA where engine was done.

I think you have your answer. If it was my airplane I’d send at least the left one off to Aero Accessories in Van Nuys CA. They did a beautiful job on the ones I had one my last Bravo. 

[PaulM]

I had similar issues a number of years ago, as it kept getting harder and harder to start the Bravo, especially on warm restarts (after years of perfect behavior).   It was loose points in the left mag.   MSC did a shop rebuild, and it has been fine since. 

I've also been seeing (twice now) the "won't start until you release the starter".. So I'm watching that mag, and will probably put in a surefly if it continues to act up.  

[toomany]

ordered a surefly yesterday - should have it in by the end of next week or early the following. It requires a hot wire from the master solenoid so i'll run the 14ga. from the battery compartment to the engine bay to save time and money. Henry Weber at LNS will do the install and land the hot wire. I'll try to do before and after comparison and post here.


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[philiplane]

Hard starting when warm usually points to the magneto. Slick mags are notorious for weak ignition coils when they get warm. 

[toomany]

On 12/30/2023 at 4:40 PM, philiplane said:

Hard starting when warm usually points to the magneto. Slick mags are notorious for weak ignition coils when they get warm. 

got the bravo back today after the surefly was installed.  starts right up w/ less than 3 seconds of prime.  orbitted lns at 10,000 and held 1300-1500 fpm on way up - da and oat were low thoigh. cht's and egt's seemed a little cooler but won't know until i get it settled in at altitude for an hr or two.  its times like these that you reslize we've been kept in the dark ages by the faa, lycoming and continental - we're in 2024 and get excited about electronic ignition.   please spare any comments on how reliable 1930's magnetos are - they are absolute junk in my opinion w too many moving parts to be considered a reliable form of ignition in this day amd age - especially when we have electronic ignition/fadec systems that draw on the order of miiliamps 

[LANCECASPER]

1 hour ago, toomany said:

got the bravo back today after the surefly was installed.  starts right up w/ less than 3 seconds of prime.  orbitted lns at 10,000 and held 1300-1500 fpm on way up - da and oat were low thoigh. cht's and egt's seemed a little cooler but won't know until i get it settled in at altitude for an hr or two.  its times like these that you reslize we've been kept in the dark ages by the faa, lycoming and continental - we're in 2024 and get excited about electronic ignition.   please spare any comments on how reliable 1930's magnetos are - they are absolute junk in my opinion w too many moving parts to be considered a reliable form of ignition in this day amd age - especially when we have electronic ignition/fadec systems that draw on the order of miiliamps 

Nice follow-up