mainewoodsstol wrote:To be honest this thread has made me a bit nervous, i just bought a 182 with monarchs. I am happy to report no leaks.

There are hundreds of airplanes with these caps, including mine, which are operating with no trouble. Just make sure they’re sealing properly and go on about your flying.

Thanks for the encouraging word on the caps. I just bought one as well with these caps. Have to fly it back to Idaho from LA next week. You can bet I’ll be paying attention! 15 years sitting in a hangar with dry tanks. I guess I should just go ahead an order the O-rings..,

I've never replaced my o-rings yet from 1990 or so. Mine has been a hangar most of that time though. Just make sure when you put the cap on that it screws all the way down. Get your head right down next to the wing so you can see under the cap umbrella.

I don't post often...but thought I should this morning.

There are numerous reports of these type of caps leaking fuel around here. Some have removed them. There have been numerous reports on this forum as well. Grant it...it may not be all.

If the issue is the caps themselves, the seals, or some ancillary part attached to them that causes it...then in the world of aviation (which I both play and work in)...there is an issue and it should be addressed.

My .02.


Macdon221

macdon221 wrote:I don't post often...but thought I should this morning.

There are numerous reports of these type of caps leaking fuel around here. Some have removed them. There have been numerous reports on this forum as well. Grant it...it may not be all.

If the issue is the caps themselves, the seals, or some ancillary part attached to them that causes it...then in the world of aviation (which I both play and work in)...there is an issue and it should be addressed.

My .02.


Macdon221

I totally agree. This is what ADs are designed for...

I had this same thing happen this past week at Sulphur Creek.

I've had trouble with my Monarchs in the past but I thought I had the problem solved by removing the chain, punching down the tab and getting 2 new million dollar o- rings last year. I even "self placarded" the fillers to insure that the ratcheting sound is heard.

Flying to Sulphur, I had no leaks. I specifically remember looking to the right to look my buddy flying off my right wing. I would have seen the contrail and he would have seen it as well.

As I took off from Sulphur, several folks on the ground there got on their radios to let me know that I was crop dusting. I returned to Sulphur and re-screwed the cap, took off and observed no additional leaks.

We've now added the "contrail check" when taking off.

For those that have no trouble with them, God bless you. For the many folks that do, they are a complete flop. This is a gas cap. It shouldn't be this problematic...............and talking to Monarch will simply elevate your BP. "there's nothing wrong with the caps".

I cannot recommend them if you are thinking of replacements.

The o ring is a design used on many automobile gas caps. I'm trying to find the right sized o ring.

That was us Mike that called at Sulfer. As you returned, I told my friends I bet he has Monarch caps.

Glad it worked out ok.

Jake

Just flew back from KWHP in my “new” 1958 182 that had been sitting in a hangar for 15 years. Put new O-rings in the Monarchs. No problem at all. The installation is about 25 years old except for mine last week when I installed new bladders and re-installed the Monarch flanges and caps. 6 hours on the plane by me and good so far. There are no chains in there and no sign there ever were.

My 185 only had the outboard caps when I bought it, and now have all 4 on my 185 (Thanks Barnstormer!), and they work perfect. Fresh O-Rings are essential. Monarch recommends new O-Rings annually to avoid issues. As mentioned somewhere above, the flappers do not seal, only the cap/o-ring does.

Replace the O-rings often - my buddy with his pristine 180 recently had issues as well, lost 7/8 of a tank in 30 minutes in an isolated and rugged area north of Lake Superior. Had it not been for his good judgement and an abandoned airstrip below he would have been in trouble. New O-rings cured the issue.

They have their issues, but an extra $50 each annual seems to take care of it.

While I agree with most of what bigrenna posts, I have to disagree with his comment that the flapper in the Monarchs don’t seal.

As my tanks pressurize (my vent tube needs to be adjusted more out of the slipstream) and stay pressurized until I go to refuel, I can attest to the fact that they seal...maybe too well. I remove the fuel cap and gently push the flapper open...pussssh! A blast of fuel...maybe a teaspoon or two....every time.

I just spoke with Hartwig about it and they said if your Monarchs are older than the early 90’s that the tiny vent hole in the side of the filler neck (forward side and just down from the top) is probably too small. They enlarged the hole slightly in the early 90’s to aid in venting. You have to take the neck off to drill a larger hole...don’t know the new size yet...and will need new gaskets to re-install...according to them. My caps were installed in the late 70’s.

My 1990 flappers seal. I use a Mr Funnel to fill my tanks and when I'm done pull the funnel up so the flap is sealed and shake to empty as much out of the funnel sump. I have to depress the flapper to let that fuel run into the tank. Like I said in another post, I flew around for a half hour a few years ago and didn't lose a drop when the cap was on the ground at my hangar.

I like some others on this thread do not post often but.....
I agree with Barnstormer....
Crap...pure crap...I’ve lost untold gallons of 100ll from these caps, I live close to Hartwig, just a few hours away. I’ve talked to them often, I’ve punched in chain retainers, removed chain, soaked o-rings in mineral oil, replaced o-rings god knows how many times, and been extremely embarrassed many many times as my 185 leaks fuel onto the ramps of many airports. Can’t even imagine how many times I’ve lost fuel going north of the 60th parallel from this junk.
Pure crap...stay away.

Bkn

To 180Marty...

My experience is the same but I haven’t tried flying with no cap!

I have them installed on the Monarch aux tanks in my 185. They are of the older design and twist on like a regular cap and have no flapper in the tank. They do not leak a drop and have been worry free.

My Monarch caps were installed in 2015, the right side has been nothing but trouble, even with new orings every 6 months. I've lost count of how many times I've landed after flying for an hour or more and found the cap had loosened in flight and my wing was stained. What's the best alternative, any suggestions? I'm ready to replace them.

After fighting with these caps for years on my dad's 182, including doing everything mentioned in this thread, we finally just put the originals back on. Glad to see they do actually work for some folks.

Customer service contiunued to tell us there was nothing wrong with the caps. I guess they were just designed to leak then...

Atlee Dodge offers teo different filler neck adapters (Wisco or Shaw) for cessnas, if you dont like the stock arrangement or the monarchs.

Bigrenna; 100% agree. Monarchs on 81' T210 since 1999- never ever a problem. Installed new O-rings once "just cuz".

I bought a C185 4 years ago and had Monarch Fuel Caps installed at time of purchase. They have leaked ever since despite efforts to properly adjust the wing fuel vents. At most recent annual I finally sent the caps and adapter plates back. They found the plates were improperly installed! After proper orientation and installation, the caps no longer leak and I am getting 3 gallons/hour better fuel flow! Don't give up on the Monarchs. I am now very pleased with my purchase.

a3holerman wrote:I have them installed on the Monarch aux tanks in my 185. They are of the older design and twist on like a regular cap and have no flapper in the tank. They do not leak a drop and have been worry free.

Yes, it's important to understand that there are different models of Monarch fuel caps. Some are the type discussed here. Others are similar to very common fuel caps found on many airplanes. These have not been problematic in my experience. They have no flapper and no chain....

I flew a 206 for a few years with the "other" Monarch caps, and never lost any fuel with them. They had flappers and chains.

MTV