I have a veco 19 with a baffle instead of a muffler on a airboat. I finally got it to start and run (the fuel tank was to low before). Now the problem is, no matter how I adjust the needle, (it has just one) If i take it past approx 1/4 or 1/3 throttle, it will die. I tried to blow on the gas tank vent tube and move the throttle at full, and I was able to get it to run at full throttle with a slight blowing pressure into the tank. I am needing to know what you guys think is the problem. If it had a muffler, I dont think I would have any problems because then it would pressurize the tank, but i dont, so what do i do to fix this? I appreciate your help very much, and I am looking forward to being a part of this forum. I have several airplanes, an airboat, and I had a gas truck (TMAXX) for awhile.

Thanks
Brian =)

I believe the gas tank is right, but just to be sure, I have the line to the carb going into the tank with one of those things to keep the tube at the bottom, and to filter it, and I have one tube that is just a vent (I used to have it on a mufflered engine), I just left it when I switched engines. The reason I changed engines, is the airboat needs approx a 15-25 size engine, and i had a 40 on it!!! LOL It had tons of power, toooo much, and was a little top heavy also.

Thanks again
Brian =)

You can pressurize with crankcase pressure by replacing one of the backplate screws with a pressure fitting I think. Somone with Veco experience needs to chime in here. Also if you are patient and resourceful you will find the proper muffler for this engine

Yes, i agree pressure would help, if putting a fitting into the crankcase would work, im all for it, if i can find a fitting. lol The baffle is the holdup i think, I was also looking at some other used engines, are all 19s the same for motor mount wise? Also will the other sizes fit the same motor mount? 19-25 is the suggested engine size. I played with it in a big puddle from our rain today, and just went on low throttle, and it was great, i cant wait to get it running good so i can trust it in the middle of our lake! =)

Im awaiting a veco 19 profesional here, there should be a way to make it run full throttle with the baffle isn't there? I mean, they wouldn't make them with just a baffle if they couldn't be ran, right? Does the baffle need to be adjusted or something. I have the fuel tank right behind the engine, almost touching it level with it, because it was lower and didn't want to work. Its there temporarily though, i hope to be able to put it back below the engine were it belongs.

Thanks
Brian =)

Brian:

When you say a "Baffle" in the exhaust I'm assuming you mean it has a throttle butterfly in the exhaust that closes as the throttle is closed. This should be adjusted to be fully open at full throttle, and be closed just as the carb barrel closes. This is the initial setting - where you start.

You have to start adjustment at full throttle, I suspect you're still way lean. As you speed the engine up, when it starts to sag open the needle until it picks up again. Keep doing this (don't take it back to idle) until you get full rpm. From this point you can work on the idle, leaving the needle alone bring the rpm down gradually, you might disconnect the link to the exhaust throttle while you're doing this. As the rpm comes down you'll probably go rich. The exhaust valve is your low speed adjustment. Leaving it open is lean, closing it is rich.

Once you know pretty much where the exhaust has to be positioned at idle, work with the link from the carb to get it to follow the throttle as needed.

Have fun.

Bill.

The old Veco was designed to run without a muffler (because they didn't have mufflers then ) so the carb is quite small to give the fuel draw needed. Because it's got a cast iron piston you need a fuel with lots of castor and total oil around 25%.

It seems the problem with yours is just a matter of fuel draw. Check for any blockages in the needle valve and then blow through it while opening the needle and see if the sound of the air going through gets louder and louder as you wind out the needle. Does it draw fuel from the tank easily at full throttle when you prime it? If not there could be an air leak from the carb (both retaining screws are tight?) or the backplate. In the worst case the piston could be too worn to seal and give the suction needed. Is the piston fitted the right way round? The baffle on top has to be on the far side from the exhaust port. Is the liner fitted the right way round? The top edge of the exhaust port is higher then the transfer port. You can check both of these just by looking through the exhaust preferably in sunlight. With the piston at the bottom of its stroke the baffle will appear to be almost on the other side of the cylinder and the top edge of the transfer port will be just visible about 1/32" above the baffle and noticeably lower then the exhaust port.

The only other thing I can think of is the carb. Unfortunately the carb I've got is missing everything except the barrel itself but from the looks of it I'd say it uses the old type where what's basically a CL spray bar locks into the barrel and rotates with it. If that's the case then there's probably just one hole in the spray bar and you shouldn't be able to see that hole looking down the carb. If the hole is on top of the spray bar looking down into the carb then that'll definitely give bad fuel draw.

Crankcase pressure won't work with a carb because it's far too high compared to muffler pressure. You'll certainly get it to run great at full throttle (you'll probably find the needle is only open maybe half a turn and it'll be VERY sensitive) but close the throttle and the tank still has full pressure inside it and it'll flood the engine.

Have a look at http://www.mecoa.com/kb/69/6951.htm

I have a Veco 19 with the muffler that was made for it way back then. It runs flawlessly with muffler pressure. If you cant find a stock muffler, dubro made plugs for the holes in the stack, then you can use a strap on muffler. Some clever use of JB weld might also plug the holes. Good luck.

PS,,,In the 70's the only thing of its size with better performance was a ST23.

I think ive got it, and it was something else, something i missed. i will post again in half an hour or so when i finish up. Will post pics too. I have it running great at full throttle!!!! Im not using the butterfly at all now!?! curious? Ill show you in a bit. Thanks for all the replies, i greatly appreciate it! Well, ill chat in a bit, gotta finish!

Thanks
Brian =)

Ok, im back with some pics in my gallery, so check them out. In the midst of waiting for responses, i decided that i would make a muffler out of some aluminum, so I got to work to fix my problem. I got the muffler done, and I was happy with how it looked, and how it helped the fuel draw, (i can now have my tank below, were it is meant to be) but it still stalled at full throttle, or even half throttle. So i tinkered around some more, and I found a air leak that I had missed before. The place were the throttle barrel rotates, it has some packing, or gasket material to keep it sealed, and it was worn out and was leaking. My solution for that, as you can see in some of the pics, was to cut out a circle of leather from some work gloves and use that! I had to use 2 layers to keep it from leaking, and I lubed the leather up with some wd40 so the throttle still moved freely. While I had the carb apart, I made sure it was clean, and reseated it in the intake and made sure I had no leaks. started her up and tuned her at part throttle, and then cranked her up and it kept running!! [X(] I was thrilled, it worked! Did some final tuning at top speed, and now it runs like a champ, and i cant wait to try it out tomorrow at the lake. The radio and batteries are on the charger for overnight, and Ill be playing tomorrow after work. Even though the muffler wasn't the problem, I liked making it, and i think it looks cool. It even quiets it down abit. I read that one of you mentioned that the baffle was how you controlled idle mixture, now that i have the muffler instead, I cant control it can I? It idles fine, however if it sits at idle for a very long time, and then i go to throttle up imediately, it sputters for abit, cause i think its running just a tad rich at idle, but it doesn't really seem to effect performance or idle, so i should be fine, I would think. The muffler tip that i welded on my muffler I made, i drilled a 1/4" hole through it, I went by approx size of other stock airplane mufflers I had. The muffler I made wont harm the engine will it? I wouldn't think it would, but I figured one of you guys would know for sure so i would feel better knowing its ok.

Thanks again for your help and suggestions, I really appreciate it, and I am glad to have found this forum. I am looking forward to learning a few things, and sharing what I know.

Thanks
Brian =)

Heres one pic, but check my gallery for more.

Brian =)

A muffler for an HB 21 or 25 will fit that engine perfectly.

Your muffler is great. With the tank that low I can see why you were having problems. I don't think that your problems are necessarly all gone. If you want to leave the tank that low you may have to put a pump on it, but try it and if it works don't fix it.

I still have a couple of these NIB... If I remember correctly (30-40) years ago, I removed the baffel.. That was prmarily to help the idle.. A company called Tatone made a strap on muffler for it... These were some real screamers ... Used to run them in the Bridi 19 sixe Super Sports....

Thanks!, i like my muffler too. I took it to the lake today, and it ran great! It was a blast. It was a little windy, or I mean alot windy, but I found a marsh like area that wasn't part of the big lake that I zoomed around on. I only had to retrieve it with my waders once, cause I hit a big wave or clump of weeds, something, and it ramped into the air and took a nose dive into the water and drenched the carb with water. =( It worked fine with the tank below, no problems at all. The only problem is that since I cant adjust my idle anyway without the butterfly exhaust, it runs a tad rich at idle, and is hard to start, but once you figure out the trick, it will start before long. Ironcross, it is a screemer! It was really fast and got to the point were it was barely touching the water at all in the back. It kind of bobs up and down when at high speed and barely on the water. Is that caused by the degree of engine tilt? How can I fix that if anyone has an idea. I built the mount myself, and it has about a 6 degree upward slant.

Brian =)

Just shim the back of the mount or engine to bring the spinner down a little and test. If it's better do it a little more. I would think that you would want it close to neutral. Does it track straight or does it require right thrust?

ill have to try that. for right thrust, do you mean trimming the rudders to counteract from the engines thrust? If so, it was to hard for me to tell today, because it was very windy, and I was constantly having to correct the boat from the winds gusts. Next nicer, calmer day i have, i will take it out again and try and see what happens.

Thanks
Brian =)