I have fuel leaking from behind my flywheel

[NooP]

I have an os cv.15 and I have fuel leaking from behind my flywheel. I took my motor apart and I do not see any type of seal or gasket in there. It looks like the crankshaft is just suppose to seal to the bearing that is there.

How do I fix this? Do I need a new crankshaft/bearing? Is it worth it, or should I just get a new motor.

Also, would this explain why I am having trouble tuning my engine?

--NooP

 

[SilentHunterKellen]

Check warranty.

 

[olds97_lss]

It depends on now much wear you have on the engine. How many gallons has the engine been through?

They do wear out over time. The bearing is all that's there to keep it sealed. I havn't had one go bad enough to do that though. But i've read about it.

 

[Çh®i§tiªñ]

Just replace the bearring(s) with a good quality sealed bearring and you should be good to go.

The problem is more common than most think. A pain in the ass to fix, but not costly at all.

A small amount of fuel leaking from that bearring is not uncommon even with a new bearring. If it is excessive, then you need to address the issue.

Acer, Dynamite, TeamBlueStar and even Durratrax bearrings are all ones I would recommend to use.

If you have a Local Hobby Shop you can go to, consult with them about the best bearrings they have in house.

Make sure you have your engine mannual in hand.

 

[NooP]

How much is exessive? I got the engine, the whole car infact, from a friend. So I'm not sure how old or how much fuel has gone through the engine. I have never really noticed it before, but this weekend I put a one check valve in my pressure line and intially my engine would flood. It would flood enough to lock the engine up. These check valves really make a difference. But anyways, I got it to keep from flooding and I notice some fuel under the flywheel. There was very little maybe a few drops, but it was there. I am not 100% sure if it was flooding or if it has always been there.

Also would/could this be the reason I am having so much of a hard time tuning my engine? I have 3 cars, ofna gtlx pro w/ force .21 p4 engine, Traxxas 4-tec w/.15 engine, and this HPI RS4 w/ and OS cv .15 engine. I have succesfully tuned my other two cars with ease except for this os engine. My other two cars start up and go tanks with out dying out. My OS engine is giving me the hardest time tuning it. I even bought a temp gun to help me tune it. I have tried running it at 220, 240, and even 270, and I still get the same result. Even new fuel lines, check valve, gaskets.

THis is my problem with the engine, I hit full throttle and it dies. I can drive it around at low throttle to mid throttle for aslong as I want, but when I hit full throttle, it either dies out on accel, or dies out when it begins to slow down. This car is really driving me crazy trying to tune it.

could this small leak be the cause? ALso, is this the front or rear bearing?

--NooP

 

[olds97_lss]

I beleive it's the front. I'd still check for an air leak around your carb neck. Pull the carb off and clean the neck and the crankcase hole it goes into with some alchohol and a q-tip. Put some high temp silicone around the neck and re-seat it. Let it cure overnight.

I wouldn't think a few drops here and there would cause this big of an issue. I mean these things leak a bit when they are worn some, but not usually enough to cause issues. At least until it really starts to leak a lot. Anywhere fuel can come out means air can get in. Air leaking in causes erratic running.

I'd check your engines cooling head. Pull it off and make sure there are appropriate shims under it and that the surfaces are clean. Tighten it back down correctly and tightly.

Is your muffler gasket ok? If your losing it when you peg the throttle, it either means you aren't getting enough pressure to push the fuel in or it's running to rich and you have to much fuel.

I used the one-way on my maxx with a OS 21 RG and I didn't like it. Made it run too rich all the time. I used it on the pressure line so the pressure in the tank would stay at a constant. It worked to well apparently.

Not to state the obvious, but did you replace your glow plug just to be sure it wasn't causing issues?

If you do go for a new engine, I highly recommend the OS 15 cv-r(x). I have 6 gallons on one of mine and it's been a pleasure to run and tune. It's still runs really well, but it's to cold and snowy to start gallon 7. So, i'm in storage mode.

 

[NooP]

Thanks for all of your input and help olds. I will definitely do all of that. I really do not want to get a new engine just yet. I am waiting for either the os.18 or the ofna .21 that are both in the small block form. I'm hoping I can get this engine to limp its way untill those engines are out. Also, just out of curiosity, what is the difference between the os .15 cv-r and the os .15 cv-r (s)? I looked up the engines you suggest and found both of those.

I am currently running an os A5 glow plug and blue thunder 20%. I did try other glow plugs that I do have, none of them seemed to make a difference.

Thanks again, I will post my results when I have them.

--NooP

 

[olds97_lss]

It's cv-r(x). The x means pull start if i'm not mistaken.

 

[NooP]

not the (X), the (s).


--NooP

 

[Candyman]

The (s) stands for short shaft. If you're going to put it in the RS4, you'll need the standard shaft. So that would be either the CV-R or the CV-RX.

 

[NooP]

actually, this is going into an rs4 nitro mini. I am pretty sure it uses the short shaft cuz I dont have a flywheel hub on my motor, but I am going to call HPI and OS to find out for sure.

--NooP

 

[olds97_lss]

Sorry about that. I thought you made a typo.

 

[NooP]

I did pretty much everything you said olds, and as far as I know, I have no more leaks. I just took the crank out and cleaned it and so far no leaks from there or anywhere else.

My car still seems to die when I run full throttle for more than a few secounds. I've tried setting it very rich to very lean and everywhere in between. I am beginning to think that this engine is dead.

symtoms= dies on full throttle. If not full throttle, it dies on decel or when it comes to a stop.

What are some signs of a dead engine?

--NooP

 

[olds97_lss]

Is there a lot of compression when you pull the starter?

From what i know, erratic running (like you have), no compression and constant over heating regardless what you do are signs of a dead piston and sleeve.

Normally, the early sign is that it won't idle at a low speed idle. There isn't enough compression to create enough of a vacuum or pressure to suck/push fuel in at low rpm's.

I really don't know though. If you've done all that you've said, there isn't much left to do, other than replace it.

Anyone else have any suggestions?

 

[NooP]

It does Idle real good. That is what trips me out. This car can idle for the full tank pretty much and keep a snappy throttle. As for compression, hard for me to say. I can say it has compression, and it is enough for the car to really hall ass. I can run it all day not going full throttle and it runs good. Just not VERY fast. I am already planning on getting a new motor. I just want to hold out for the new OS .18 or the ofna picco .21 small block. Thanks for the help OLDS.


--NooP

 

[NooP]

I was just going through my engine again and I noticed I was missing a washer that goes behind the collet, which is all behind the flywheel. Because that washer is missing, could that be the reason for my fuel leaking, which is giving me an air leak, which is making my engine run like sh*t?

The HPI part number is A804 and here is a link to which washer I am talking about.

http://www.hpiracing.com/index2.htm

--NooP

 

[NooP]

Well, I put the washer on and the car runs A LOT better. It's not 100% running good, but it only dies on full throttle after a pull longer than 15 sec or so. And even then, I can keep it alive sometimes by snapping throttle a few times. Since putting the washer in place and helping the bearing seal, I gues it would be safe to say that the front bearing need to be replaced. I guess I dont mind spending another 15 dollars on this engine. Thanks for the all help.

--NooP

 

[nitroboi36dofuss]

go with the os21 reliable,strong,fast,tough;
i ran mine at 410 degres and it still runs, os rg21
:flamer:

 

[JPK]

I am new to Nitro, But I had my new motor do this same thing.
So much so I thought I was reading my post. I found the fuel from behind the clutch was because of being to rich, I had resealed the carb 3 times, The third was the charm. & replaced the new fuel lines. Removing the primer took out some air I would see in the line just after running hard. My truck has now run three tanks & has ran great. To start I plug exhaust for three pulls, turn on radio, open & close throttle one time, put on glow starter & it starts in 2 pulls even @ 50 degs.

 

[Çh®i§tiªñ]

Let me know how the bearring works out.

If that washer doesn't need to be there, get rid of it. Last thing you need is one more piece of metal spinning around at high rpms rubbing on your seals. If you have a small gap between your flywheel and bearring, thats ok. The goal is not to have a slipping flywheel (thus, the collet).

I think your solution is in the bearrings.