deslok113

This is my first build as I said before, when I needed some help with the cooling config. Now I have another problem. The hull is used in good condition, as stated before its a deep -V 36" I believe. It had an old OPS .65 in it; the fellow who sold it to me said that it was old and I should rebuild it. But I decided to buy another engine for it. I bought an OS Max .65. I put in new tank, tubing, fuel filter, etc. The servo's and radio gear I got from an RTR; I had that hit an 18' bass boat on the bayou I live by head onSMACKEROONIE!!!! A dumb move on my part to run on a bayou with high traffic, but at least the bass boat guy wasn't p.o.'ed even though I scratched his hull a little. :-)
I put it together correctly found the proper motor mount on the dumas web site, tested the electronics, and leak tested it. Today was to be it's test fire day. I connected its cooling inlet to a water pump to pump water throught the head when I was bench running it. Next I tried to fuel the new tank. Fuel gushed out of the carb all over the inner bottom of the hull. I pulled the fuel tube off the carb by the filter and plugged it with a small screw driver. I filled the tank the rest of the way. I unscrewed the new glow plug I put in it and used my electric starter to blow out the excess fuel from the cylinder. I reconnected the fuel line to the filter and heater the plug, again fuel gushed out of the carb and the cylinder filled up with fuel. Should I punch a nail through the extra tube fitting on the tank rubber cork? or loosen the cork? what am I doing wrong? Help is greatly appreciated.

jetpack

My Feedback: (1)

There's two ways to set up a tank.

One way is to use two lines, one being your exhaust pressure line and the other your fuel line to the carb. To fill, you disconnect or use a T fitting before the fuel filter, and the pressure line is your vent. You either close the needle or use a hemo to stop flow to the carb if using a T fitting. The T fitting will need a fuel line plug when your ready to run.

The other way is to use three lines, and use the third line to fill, and then plug the filler tube when ready to run. These two methods the only thing you have to buy is a plug, or make one.

You're trying to fill using the exhaust pressure line and there is no place for the air to go, so it is forcing fuel into the carb.

How do you have it set up right now?

What most people use is a fuel filler valve. It shuts off fuel to the carb and pumps it into your tank without removing or having to block any lines. It fits before the fuel filter and the carb. There are several manufacturers, but DuBro and Sullivan are the most popular and easy to find.

deslok113

I have two lines; one to carb; one from the exhaust to pressurize the tank. It seems like too much pressure is built up in the tank and fuel goes everywhere once I try to start the engine. On some RTR's, I've had to prime the engine by putting my finger over the exhaust to get fuel to go to the carb. This one, when the starter turns the engine, the cylinder fills up with fuel and the carb spits out fuel. I clear the excess, try again and same thing. Too much fuel is getting to the carb through too much pressure. My question is should I drive a nail through the rubber stopper or loosen up the screw, to relieve the excess pressure??? Thx

jetpack

My Feedback: (1)

Try running without pressure, use the exhaust line for just a vent.

Sounds like you have good enough draw from just the carb. Not every setup needs exhaust pressure, only use it when you need to. Its best to try without first, thats your best setup. Pipe pressure is only a secondary step if it dont work.

Your exhaust pipe is wide open, it shouldnt push any pressure until the engine is hitting high RPM's and even when it does, the exhaust outlet releases any excess pressure the tank is trying to keep.

deslok113

Thx man I'll try that.

Ron Olson

My Feedback: (1)

I have an idea that the fuel tank is too high and that it's siphoning fuel out of the tank even while it's not running. Try pinching off the line with some kind of clamp until it fires then take it off.

f16man

Yea , or the hs needle is turned out a mile.

deslok113

I'm really getting discouraged with my first build. Maybe I should stick to what I know bestelectrics. Nitro is kicking my butt. I tried to lean out the fuel/ air mix today to stop the engine flooding. I should've thought of the HS needle!!! I got the engine to fire only for an instant and then flood again. I would clear the cylinder then try again. The engine would only fire for an instant no matter how I turned the knob. I don't know why I didn't think about the LS and HS needlesI know what you're thinking, dumb Noob.
To clear the excess fuel I'd remove the glow plug, detach and plug the fuel line, and spin the flywheel with my starter. The fuel would spit out of the glow plug hole and out of the exhaust pipe. I'd then adjust the fuel/air knob and try again. Finally, after many tries I accidentally screwed the glow plug in the wrong way and stripped the head, worse yet the glow pug is stuck in the head; and the worst of all my hobby shop guy said that it will be hard for him to find a replacement head for the OS max .65 because it has been discontinued!!! He said that parts are still available but he has to call and email around to find it for me. Once I get the replacement I'm considering paying my hobby shop guy to tune the engine and the selling or trading it for another
BL electric. I like Nitro, but I had bad luck with all of the ones I've owned, the first Nitro I had was an RTR hydroplane, piece of junk Its hull cracked all the way around I still have the .18 it came witha vertex. My second RTR ran great until it RAN into a bass boat. And the third is the one I'm buildingor attempting to build now. My hobby shop guy reminded me that BL are good but Nitro run times are usually longer than BL electrics unless you buy the mega expensive Lipo batt's. He said even then you run, charge, run charge. I'm just a little discouraged considering all the time and money I threw into this project and I still have to spend more and will probably have to have someone else make the engine run for me. Any words of wisdom/encouragement would be appreciated. Thanks for help and reading my Nooby ravings.

Dan S

I think the glow plug problem is fixable without replacing the head button but lets wait and see if someone can chime in on that one.

do you know how many turns out you have on each needles?

and pics of your setup would also help a lot.

Dan

jetpack

My Feedback: (1)

As far as tuning the engine, nitro engines have to be tuned each time you start them up, even between fills, sometimes. Nitro motors are very dependent on tempurature, humidity, and barometric air pressure. No two days are the same, ever. I have seen more than once people that have never moved the needle on their carbs, simply because they think the factory setting should never be touched. Thats the easiest way to run into trouble.

Learning how to set the high speed needle and what it should act like or sound like after it hits the water has to be learned, and it does take a bit of heartache to get there if you are trying to do it alone at the lake.

Keep a rowboat handy, because even when you've learned everything you think you should know, there still will be stalls on the water, or flips. You have to accept the frustration until you learn. If you can find anyone who has run nitro motors to come with you to the lake, please do it. It will help tremendously.

Don't throw it all away just because you're frustrated. Look at it as a good goal to learn . Once you get the hang of it, there's nothing that compares to nitro if you like hearing engines. Nitro boats are very much a "tuner's" playground...there's always something to chase around to tune them, and get them running the best as possible. Much more of a challenge than watching a battery charge. Battery power can be a bit bland, anything after that is called expensive.

You haven't destroyed anything that can't be fixed with only a small outlay of money and finding the right guy. The head can be taken to a local machine shop, and a thread fix called a "Heli-Coil" can be put in, but it IS a special order to get the right thread size.

All these questions can be solved, so don't pitch the whole works quite yet....

Meanwhile, see if your hobbby guy has a manual for a nitro engine handy, and ask to take it home and read it. Any manual will do, because all nitro engines are set the same way with the needles.

If you want to visit the nitro engine forum, or even the RC Car forum and do a search on how to set the high speed needle, you will catch on. It is a very large subject with many many aspects. You have to remember even though these engines are small, everything that involves tuning them is big with lots of variables that have to all work together that you have to consider. Stepping into running nitro engines for the first time can be overwhelming, but there are basic easy steps to follow to get there.

It does sound like you do have at least a little bit of running nitro under your belt, you just have to get past the humps now, and that's not bad.

deslok113

I don't know how many turns out are the LS and HS needles. I believe one of the needles is located below the carb and the other is on the side. I'll have to confirm which is which by consulting the manuel. My hobby shop guy gave me some much needed encouragement as did you JP. I appreciate it greatly. My hobby shop guy thinks he can get a replacement head for $25. That is not bad. So, I'll research the tuning of nitro's in general as well as look up the specifics on the OS max .65 marine. My hobby shop guy says that that engine is dynamite and if I learn how to tune it right I'll be amazed at the performance it can give.
You're right JP I was/am one of those people who just left the factory settings on the RTR nitro's I've owned. This project is kicking my butt because there are no factory settings on this engine. I have to set it myself and I'm doing so blindly. A good friend of mine says I should start using my big boat as it was intended (to catch Bass) instead of as a chase boat for my models. I started taking model boats on fishing trips when the fish weren't biting. The last time I took the big boat out I left the fishing poles at home! I brought my old 800 brushed cat hull with 19.2v pack and this boat with the old OPS that was in it. It took a little while to get the OPS to run but I got it running and had my nephew drive the big boat. The r/c boat was leaving us behind, so i told my nephew, give her the gun with a downward motion on my arm to simulate pushing the big boats throttle wide open. My nephew said, "man, that's all you got" The speed-o-meter on my boat was pegged inbetween 47 and 48 mph!!
Unfortunately, that old OPS crapped out on meprobably had something to do with me running it too long w/o water running through the heador actually the case on this OPS. The guy who sold it to me said it was an old engine and he used to race it so I knew it wouldn't last too long. I pulled it, to replace it with the OS max I added a new paint job, new servos, reciever, and transmitter from the crashed hull, and new rudder. I kept the original running gear. So far I've been able to make the OS Max engine run for about 2-4 seconds. Well enough rambling thanks again and I'll keep trying to learn about Nitro. I'm not ready to give up yet.

f16man

I have all the stuff to fix the glow plug threads send me your head if you want it fixed no charge.