OS outboard questions

[mike the snake]

I'm having trouble starting my OS 21 outboard.

Presently 25% nitro. I couldn't get it to start using 65%. It starts using 25% but not easily or consistently.

The tune is:

LSN, set so after running for a bit, allowing the engine to idle down for a few seconds and gunning it, it takes a second to clear out, but revs smoothly. Cleared out, throttle response is good, revs quickly from idle to top RPM.

HSN, I leaned it until it fell on it's face at WOT, then backed off 1/2 turn, where it runs great.

It acts this way regardless of plug heat or brand.

I'm pretty sure the tune is pretty good, once running it runs well.

Even after running a tank, or during tuning where I brought it in often, it just does not want to fire easily.

Is this normal? I know the tune is decent. It doesn't pop until I prime it, but then it quickly fills the pipe with fuel. It acts like it's drowning the plug and/or dead glow driver.

The starter rotates in the correct direction, but the engine almost always fires up backwards. a little pressure from my fingers on the cone at idle reverses the direction.

I want to tune and run it using 65% fuel but it will NOT start using the OdOnnell 65% boat fuel.

I'm going back to the lake now to see if I can figure this thing out.

Any help or advice would be greatly appreciated.

 

[Tim_Duggan]

Set the idle up a little faster with your throttle trim. Helps with the kicking backwards problem.

Plug - use a K&B 1L or a McCoy MC-59. Keep the LS rich and pinch off the fuel line to start it, releasing ones it fires. Keep blipping the throttle until you get it in the water. They can be a bit tricky when they are new and still rather tight at TDC.

Once you make the switch to 65% - you will have to richen the needles up or it will go waaaaay too lean. Also - thats a good time to pull the head shim out. Most guys run the OS with no head shim at all.

 

[mike the snake]

Thanks very much for the tips.

I went back, gave the 65% another try. I got it fired, but it would die after any full throttle action, so I richened the LSN 1 turn, and richened the HSN til it didn't zing too quickly to be safe. It never ran, kept dying, as soon as I put the 25% back in and put the needles back it ran perfectly. I suspect the fuel I got is stale.

When I ran Odonnel in cars it was clear, this is 65%boat so different, but also very brown in color. Is OdOnnell 65% Boat brown in color?

Set the idle up a little faster with your throttle trim. Helps with the kicking backwards problem.
Plug - use a K&B 1L or a McCoy MC-59. Keep the LS rich and pinch off the fuel line to start it, releasing ones it fires. Keep blipping the throttle until you get it in the water. They can be a bit tricky when they are new and still rather tight at TDC.

Once you make the switch to 65% - you will have to richen the needles up or it will go waaaaay too lean. Also - thats a good time to pull the head shim out. Most guys run the OS with no head shim at all.

 

[ozbryan]

Mike that fuel sounds a bit sus being brown.

 

[Jerry Dunlap]

The oil used in O'Donnell Boat Fuel gives the fuel a brownish color.

JD

 

[Mike Hughes]

It should not be brown. It may have a slight yellow color to it when it is new. Mine would turn some what of a orange hue after 2 yrs or so. It still ran good. If it is brown, than I would say the fuel is bad.

Mike

 

[Jerry Dunlap]

It should not be brown. It may have a slight yellow color to it when it is new. Mine would turn some what of a orange hue after 2 yrs or so. It still ran good. If it is brown, than I would say the fuel is bad. Mike

I was running some O'Donnell yesterday that I had put in a metal can and one of the other guys asked if I was running root beer for fuel.

JD

 

[mike the snake]

It is the color of light root beer. Looks like Tea

Thanks for the responses.

I really tried with the 65%, I could not find a basepoint.

It should not be brown. It may have a slight yellow color to it when it is new. Mine would turn some what of a orange hue after 2 yrs or so. It still ran good. If it is brown, than I would say the fuel is bad. Mike

I was running some O'Donnell yesterday that I had put in a metal can and one of the other guys asked if I was running root beer for fuel.

JD

 

[mike the snake]

Thanks very much for the tips everyone.

Today I'm going to try 45% Byron's, the MC59 plug, and remove the head shim.

How many gallons of fuel should I expect to get out of this OS?

It is the color of light root beer. Looks like Tea

Thanks for the responses.

I really tried with the 65%, I could not find a basepoint.

It should not be brown. It may have a slight yellow color to it when it is new. Mine would turn some what of a orange hue after 2 yrs or so. It still ran good. If it is brown, than I would say the fuel is bad. Mike

I was running some O'Donnell yesterday that I had put in a metal can and one of the other guys asked if I was running root beer for fuel.

JD

 

[topfuel443]

It depends on many things. If you overheat the stock sleeve, the nickel liner will start to chip, and you will lose performance very fast. If you dont overheat it, it should last you atleast 6-8 gallons before replacing any parts as long as you do enough maintenance. Even then, you can get away with only bearing replacement.

I see a LOT of these engines come through my shop, and some of them have been easily over 10 gallons and look like new, and I have had engines that had 3 tanks run through and its completely shot.

Bottom line, take care of your stuff. If you are not sure how to flush out an engine, ask someone. You will get a million different answers, but it comes down to getting ALL of the water out, and then following up with lubrication.

BTW, I would say 80-90 of the guys who race the OS, use 60% fuel or higher. They love nitro. Sounds like you are heading in the right direction.

~James

 

[mike the snake]

In removing the head shim, there is a score in the sleeve. I'm bummed.

I've properly run and maintained this engine. I've spun it out and stalled it a few times, neither time did it suck water, but I removed the plug and flushed each time to be safe.

After use I burned off the fuel inside, WD 40, and used after run oil. Everything blown off, flex shaft removed and relubed, as well as popping the motor off the lower and cleaning/drying.

I can't tell whether it is from the nickel flaking, looks more like something was ingested. The score is just at the top of the sleeve, a couple milimeters long, it doesn't go deeper than the bottom of the piston. I know the motor has not ever gotten hot or run lean.

Compression is still really great, it barely bleeds down.

I can catch my fingernail on it though, it's there. Is it OK to run if the compression is still good?

I'm going to just get a new piston and liner and start over. Getting frustrated, but going to stick with it.

It depends on many things. If you overheat the stock sleeve, the nickel liner will start to chip, and you will lose performance very fast. If you dont overheat it, it should last you atleast 6-8 gallons before replacing any parts as long as you do enough maintenance. Even then, you can get away with only bearing replacement.
I see a LOT of these engines come through my shop, and some of them have been easily over 10 gallons and look like new, and I have had engines that had 3 tanks run through and its completely shot.

Bottom line, take care of your stuff. If you are not sure how to flush out an engine, ask someone. You will get a million different answers, but it comes down to getting ALL of the water out, and then following up with lubrication.

BTW, I would say 80-90 of the guys who race the OS, use 60% fuel or higher. They love nitro. Sounds like you are heading in the right direction.

~James

 

[topfuel443]

Probably sucked in a glow plug element. If its still runs good, run it till it doesnt. especiallyif you are just sport running at the lake and not racing. I have seen many of them scored also, and still run well. If it still has good compression/seal you should be ok.

~James

 

[mike the snake]

Thanks. I fired it and it's fine.

I checked an RG 21 piston and liner (checking to see if the parts were common), close, but no cigar. Looks like the parts Will fit, but the XM piston is different and the sleeve is chrome not nickel.

I wonder why they used ABN instead of ABC.

Is there a good place that sells OS XM replacement parts?

Probably sucked in a glow plug element. If its still runs good, run it till it doesnt. especiallyif you are just sport running at the lake and not racing. I have seen many of them scored also, and still run well. If it still has good compression/seal you should be ok.
~James

 

[moparbarn]

you have been talking to him, james/topfuel443 is your one stop o/b - tunnel (and more) store! plus, one of the better people you will ever meet . you're welcome, james .

 

[mike the snake]

GREAT! I much prefer to support my LHS or buy from a recomended source.

I'll order the stuff I need today.

 

[topfuel443]

Hi Mike, you have a couple options. The RG sleeve certainly fits in the OS, and is what many of the racers run, including myself. I have the OS RG sleeve kits in stock. It comes with the RG sleeve, modified to fit in the case, new piston, wrist pin, rod and circlips. All you do is drop it in. This totaly gets rid of the nickel problem, as you mentioned. The RG kits are $110.00 shipped to the US.

I also have the stock Piston and sleeve sets (no rod)in stock, they are $90.00 dollars shipped to the US.

In your PM, you said you were running the HTB pipe, thats a great pipe, but if you are running the stock timing (namely the exhaust), you arent really doing much. The stock timing runs much better with the stock muffler. If you are going to run the pipe, you need to adjust the timing. We do that also, for a small fee.

I have the props you said you wanted, just let me know how I can help.

~James

 

[mike the snake]

Thanks very much James! I'll order the parts and props shortly.

I see what you mean about the timing changes, the pipe really hasn't improved performance as of yet, but I also suspect the prop is a little tall. It's a Grim Racer 40x53

I ran the boat today, played with tuning both the hull and engine, and I have what I think is a good tune, nice and fat, runs good. I ran it today with no water and it still never got over 140, but that's about twice as hot as it was running, it liked the heat. Stuck at 40 mph however.

If I set the prop high and level, it airs out better, bounces, and goes an MPH faster, but when I angle the shaft down a degree the boat comes alive in the turns but rides a little wetter. I THINK that with the right prop it will go faster.

Hi Mike, you have a couple options. The RG sleeve certainly fits in the OS, and is what many of the racers run, including myself. I have the OS RG sleeve kits in stock. It comes with the RG sleeve, modified to fit in the case, new piston, wrist pin, rod and circlips. All you do is drop it in. This totaly gets rid of the nickel problem, as you mentioned. The RG kits are $110.00 shipped to the US.
I also have the stock Piston and sleeve sets (no rod)in stock, they are $90.00 dollars shipped to the US.

In your PM, you said you were running the HTB pipe, thats a great pipe, but if you are running the stock timing (namely the exhaust), you arent really doing much. The stock timing runs much better with the stock muffler. If you are going to run the pipe, you need to adjust the timing. We do that also, for a small fee.

I have the props you said you wanted, just let me know how I can help.

~James

 

[Ron]

Mike what ever happend to your setup?