Utopia 185 M2 Carb'd - bad Idle and choking with quick WOT

[hyfly]

Gentlemen,

I have some issues with my Utopia, when applying full throttle instantly, the engine is choking.
When I built it up easily it will go to 5800rpm with no problem.

Carb's are ultrasonicly cleaned 1 month ago because it thought that would be the problem.
I was reading about some "highspeed stator" here on the forum, could that be the problem?

Or is this issue due to bad plugs?
I am running 1:50 mix and the top speed is 45MPH.
Idle when warm is shitty too! hanging around 900/1000 rpm and stalls now and then.

thanks!
Stefan
The Netherlands

 

[henryb]

This is really a question for Dr. Honda, but I haven't seen him around this forum in a few months?

Anyways, it sounds like your idle is set a bit low, I think the factory calls for 1100rpm idle.

You said you are using a 50:1 oil mix? I'm guess you have by-passed your oil injection system? If not then this would be a problem!

I know Dr Honda always said that you can tell alot about what is going on in the engine by looking at your spark plugs? Maybe you could take them out (mark each of them where they came from) and bring them to a good marine mechanic that knows Mercury outboards (as essentially that is what you have... with a Sport Jet Pump instead of a lower unit)... he might be able to give you some advise?

 

[hyfly]

Hi Henry, thanks for your quick reply.
What happens to you Challenger when you floor it? Does is just jumps out of the water or needs the engine time to "think"?

I run premix with a bypassed oil pump, So thats all oke.
Nex time I will turn out a plug and take some pictures.

to be continued....

 

[henryb]

I will have to give that a try this weekend, as I normally bring it up on plane before going to wot. But if you you were pulling a skier or something, you may need that instant hit of power! I will let you know.

I know last year, my engine would accelerate fairly consistently to full speed without much hesitation.


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[hyfly]

Oke, would be great.
Mine is hesitating as well as I am on plane (25mph), and then floor it.

can you try that too?

 

[henryb]

Out on the lake today, tried the idle to WOT blast... Engine jumps to 4500rpm's right away, then it continues to creep up to 5600rpm's. Takes about 5 seconds total. No hesitation or coughing.


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[hyfly]

Henry, thanks for the answer, and sorry for the late reply.
I solved the problem partly with new sparkplugs, but is still does not feel right.

Is there a way that the timing could be off spec?? So not enought pre-ignition when idling cousing it to stall now and then?

How do I set Idle timing? I found something regarding WOT timing only.

 

[henryb]

Well, I'm glad to hear you are making progress. Regarding the timing, yes timing can be adjusted... however that is not something that I have done on these engines. I think I would refer that job to Dr Honda for advise.


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[Dr Honda]

With the original comments... I would think that your carbs are sill not right. The "Ultrasonic" cleaners don't always get the bypass ports cleared out. That takes a solvent, and compressed air. (The only way to verify) So.. if this was my boat... I'd have the carbs off again.

But, as with any 2-stroke... with running issues... I change the plugs (looking at the color of the old plugs) and check the compression . Poor performance, and idle can be caused by a cyl or two starting to get low.


As far as the timing.... have you changed the linkage?? If not... it's probably fine. But to check it... get a timing light, and just check it. The procedure is outlined in the manual. Put the degree tape on the flywheel... start it up, and check it with a light.

 

[hyfly]

Dr Honda, thanks.
I'll go trough everything again.

Compresson check and check timing.
For the carbs, they have been cleaned with special carb sovent and blown through with compressed air, so this should be OK.

The colour of the old plugs were a bit darker then the "coffee with milk" colour.

 

[Steves23]

I'm not sure if this is true with carb motor on these boats but it is with my snowmobiles. Eliminating the oil injection system only gives you your premixed ratio to the motor. The oil injection gives you a variable ratio depending on throttle position. Maybe at idle you are loading up your engine with oil and it takes a second to try and burn it out. I could be very wrong and i'm sure Dr Honda will elaborate on this statement.

 

[hyfly]

I know that is true, also with these engines.
It can make the engine idle a bit rougher and smokier but it should Idle....

The bogging also occurs when going from half throttle to WOT.

 

[Dr Honda]

Steve... you are right. At idle... I believe the 210 engine will go as high as 90:1 to help cut smoke. (the 240 will go to 120:1) But loading up is more than just oil. Basically... a 2-stroke relies on the dynamic feeding though the crankcase. (The velocity of the air) At idle the velocity is low, and fuel will actually pool in the nooks and crannies. (so we run a little rich at idle) Then... when you get back on the throttle... you gulp that extra fuel... and that's what we call "Clearing out".


With that said... going pre-mix will make you foul plugs, and smoke at idle.


Let me look at the parts explosion a little on those carbs, and I'll get back to you on a few more thoughts I'm having.

 

[henryb]

From what I have read, the oil injection on these engines will vary from approximately 50:1 ratio at idle to 100:1 at higher engine speeds. So if you are by-passing the oil injection, and running 50:1 in the gas tank, everything should be equal at idle. You will just be burning more oil at higher speeds. There have been a number of members who have performed this oil by-pass.


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[Steves23]

Once again I don't know what these carbs consist of or if they are like my old 98 Challenger with the twin 787's but most have Jets. Pilot jet would be for idle. Main jet would be for mid to WOT. I know you said you cleaned the carbs but varnish and dirt can still clog these jets up. Like Dr Honda stated, Take them back off and dig into them. Make sure float/needle/seat is not sticking and adjusted properly, Vacuum leaks, Broken/damaged Reeds. Idle/Air screw set properly. I'm just thinking of things I had to do to my 787's. I have no clue if your carbs even have any of this stuff. Just trying to help

 

[Dr Honda]

Yep.... as Steve said... take them apart, and verify EVRYTHING !!


But, when you throttle up... does is just bog, and cough a little... or does it try to die???


1) If it tries to die: You are lean... and there is something wrong in the carbs.

OR...

1a) The reeds are shot. If they don't seal... then the starting will be hard, and the idle will be poor. Higher RPM's will help mask small reed issues. SO, I don't think they are busted, and missing completely, but a couple may be cracked. (carbs need to be off to get to them)


2) If it's bogging: then you are rich. In this case, I would check all the idle mix screws. They are a standard fuel mix... so turning them in will lean out the low RPM mix. BUT... I would start with making sure they are ALL at the same spot. There are 6 of them... one on each cyl.

OR

2b) make sure your enriching system isn't leaking. If it is... you are just dripping fuel into the cars all the time.

 

[hyfly]

I think it is leaning out when pull it to WOT, its not coughing but "waiting" to go to the higher RPM's.
What are the reeds? And what do they look like?

Thanks!

 

[Dr Honda]

The reeds are flexible valves, and allow the air/fuel mix to flow into the engine. They are mounted in cages directly behind the carbs. You can see them once the carbs are out of the way. On the 210 engine... I THINK you can remove the carb manifold... with the carbs in place, and get to the cages. (But there may be too much junk in the way with the carbs on)

They look like this...

 

[henryb]

Are these the parts you were referring to a while back, for getting higher RPM's and a bit more power by putting in a set of customized reeds?


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[Dr Honda]

Are these the parts you were referring to a while back, for getting higher RPM's and a bit more power by putting in a set of customized reeds?


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Yes... but honestly... over the years, I've played with most of the aftermarket reeds... and none of them make a huge impact. On the 210 engine... you have a smaller cage. If you replaced your engine case (or cut it out) so it could take the big cage... that will make a HUGE difference in performance.

Here's the back of my engine. (after welding a big hole closed, from where the connecting rod came though) You can see that the place the cage drops into is the full width of the manifold. The 210 engine is about 20% shorter. Also, on the cage above... I have 5 reeds across. Yours is only 4. (but there are 7 reed performance cages with narrower reeds)

 

[Dr Honda]

Here's the reed end of the 210 and 175.

 

[hyfly]

Ahhhh reeds! We call them membrane's.
Haven't checked those but as you said they do not point out shitty idle.....

Tomorrow I head down to the harbouw with my timing light and compressoin gauge, see what she has to tell me....

 

[henryb]

Yes... but honestly... over the years, I've played with most of the aftermarket reeds... and none of them make a huge impact. On the 210 engine... you have a smaller cage. If you replaced your engine case (or cut it out) so it could take the big cage... that will make a HUGE difference in performance.

Here's the back of my engine. (after welding a big hole closed, from where the connecting rod came though) You can see that the place the cage drops into is the full width of the manifold. The 210 engine is about 20% shorter. Also, on the cage above... I have 5 reeds across. Yours is only 4. (but there are 7 reed performance cages with narrower reeds)

So how big a job is it to "cut out" for bigger cages? And which cages would you put in a 210 engine?


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[Dr Honda]

So how big a job is it to "cut out" for bigger cages? And which cages would you put in a 210 engine?


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It's a big job. Realistically... you need to split the engine in half. (no safe way to do it together)