1993 140 Looper, new to me low Rpm roughness, and couple questions.

[cfauvel]

hmmm...you speak of idle mixture screws, but the model number doesn't support that.
your manual speaks to thermostats (like i have ) that are plastic with the thermen (sic) inside, but you don't have that.....I am suspect we have the right model number.

when you ran the motor and it didn't warm up enough....were you in the water or on muffs? Try cutting back the amount of water on muffs....or put the lower unit in a large tank/bucket..

I assume you have part 38 in the block...

if you are too cool, then at least you know the stats are working....

what are you using to measure temperature ?

 

[rothfm]

Thanks

My manual matches model number on bracket, i can tell motor is all original

Manual does talk about initial setting of 2turns out on the idle adjustment screws on front cover

The Book does show the same metallic thermostat I have, but shows it goes into a housing with seperating halves....however the BRP site breakdown does show exactly what I have.

Part 38 is in there.

I use a thermo gun, and measured several tests both in water, muffs and in a barrellat idle, and after a long hard run...

Temps at idle take forever to reach 80-90 After a long hard ocean run, barely 75. On muffs with limited water i may get 100

I actually disconnected quickstart orange wires and grounded the harness-side wire to the port stat....so i could better control the idle as its so cold, fast start could never kick off.

Looked at those stat chambers for an hour closely and i believe now i know how they work...seems they should be as designed.

First looper, i really really know the crossflows and its cooling.

 

[cfauvel]

you're so right...completely missed part #9 in the following link

wwwDOTboatsDOTnet/parts/search/BRP/JOHNSON/1993/VJ140TXETF/CARBURETOR%20AND%20LINKAGE%20-%20"F"%20SUFFIX%20MODELS/parts.html

WTH?! why have an idle mixture screw AND an idle air bleed....yikes...2 turns out is just a starting point....you may need to adjust them IN or OUT a bit

Ideally you'd have a CFM meter meant for cars' carbs to get them to all flow the same rate at idle.


I assume you took the temp measurement at the head, right? is the gun set up for Celsius ? 70-80 C nets 158-176 F....75C = 167F

 

[rothfm]

Thanks for hanging in there with me, appreciated


Driving me nuts thinking about this.

I just happened to google "1993 johnson 140 thermostat" for grins

And a pic for one on ebay comes up, and it appears it has that domed shaped cone on one end, like the pic in my book....unlike the brp website...,maybe that website diagram omitted the "holder halves"?? Ive seen manual discrapancys before.

A telltale sign is the backside of the rubber diaphrams are a bit worn in a "champhor" at an angle around the center hole, almost appears to match that domed looking thing on ebay ,and my manual

I wonder if that in fact is what i need?. My manyal says to unscrew the halves, remove vernatherm. And it says when installin into head, threaded end goes out.

I dont have halves and nothing is threaded!!

I need a drink!

 

[rothfm]

Did alot of online research and part number cross ref among different years.

Still dont know how this info affects me but i found that the internals of the stats changed from 1992 to 1993. Im a 1993

Got a feeling my book even though it lists my model and year(orig oem book), is still referencing the prior design

In 1993 they started with the large plastic housing portion that sits in deep, and the vernatherm, without a screw-together shell (domed end and a threaded shaft out the other), sits in it with springs.

Even the style of the stat outter cover changed apparantly to accomodiate this.

So, if the BRP online diagrams are correct, i seem to have the proper items installed

One diaphram has a tear, and doesnt have the integrated "cup", the other does. The other that does is missing a small ring.

I will make them match the BRP diagram with new diaphrams, and see what happens.

They nearly match the diagram i posted above, so seems i should still get some heating up action. Will test/post after getting new diaphrams and thier cups

Man, this shouldnt be so hard, should it? Yikes. Im typically shooting heat issues onnother motors, not Lack thereof!!

Thanks all for any additional insite you can lend....,particullarly if someon has this year motor.

 

[cfauvel]

ugh weird design...the plastic vernatherm housing was so simple and easy to understand....there must have been a reason.


that was supposed to be VARYING loads

This motor should be running hot....I don't get it....

 

[rothfm]

Haha, appreciate the thermostate "play-by-play" !!

I stared at that setup last night Envisioning how it was supposed to work!

That is the same conclusion I have come up with-agreed

My theory is that one of the diaphrams with the small tear isnt sealing??

The other head: doesnt have the small cup #49 that holds spring...doesnt seem that has much effect, but who knows!

I do appreciate verifying how those work, helps alot!! I agree with that

Gonna get some diaphrams and those cup holders and try.

Agreed they should be sitting in the Sealed position, and looks like they are....water has to be getting by

 

[rothfm]

A last tidbit....

Crossflows im familiar with, as soon as they start there is a teltale. I know its post impeller, pre-block

Are these loopers the sam, meaning the teltale is gonna show as long as impeller is turning?

Or is it a post-block setup?

On the hose it takes a bit to make a pee, but my flusher is crap too.

Or if post-block, maybe the stat chambers are filling, bieng mostly stopped up by states, until i begins leaking by, and this leaking prevents warm up

Was pondering getting the older style stat covers and the simple components pre-1993!

I gotta stop thinkin bout this. Got a headache

 

[cfauvel]

Was pondering getting the older style stat covers and the simple components pre-1993!

you would need the insert that fits into the block that the cone fits into....but it maybe possible....that bad thing about that is the poor guy that gets your engine next...

on my engine 86 looper, the telltale pees as soon as enough water has run up the pickup tube and filled the block...then pees stronger when stats open up.

I start to worry if it doesn't pee within a minute.


I would think that both sides would need cup #38....without it I can't see how the spring 44 doesn't fall into the block...

 

[rothfm]

Thanks. Currently i have that rear "cup insert" at the back.

Gonna examine em again tonight. Beating this one to death

Thanks for helping. Seems my parts mostly match what i should have.

 

[rothfm]

RESOLVED???

Hmmmm....Well. For those that have followed this....I made progress. However I dont quite understand the relationship!

HOWEVER, the motor now idles really really well, and a pleasant surprise after getting it to idle.....the temps went up to NORMAL with no other cooling work!!!! Please help me to understand.

THE SCOOP:

I tried everything with the stat components. Had a OEM manual descrapency VS the BRP site diagram. But I managed (with help Cfauvel here) to verify my stat components were correct. Tonight I took them apart and back together again, after testing the vernatherms, and sealing up the cover gaskets.

Being so frustrated, I decided to leave the low temps issue alone for awhile....and look toward the rough Idle issue anyway. Holding off on swapping the VRO with a spare, I decided to go for the front 4 adjustable Idle air bleed screws.

I was surprised to find them barely 1 turn out from seated...My book calls for starting at 2 turns. With motor off I went to 2 turns, fired it up and immediately noticed a difference in smoothness and less smoke. While Running, I went an additional 1/2 turn on each--it got even better. Went to 3 turns from seated-and stopped there. I hadnt noticed how much it smoked, until alot of that went away also.

By the time I finished celebrating, I put a hand on the Heads, and could feel heat!! The IR gun showed 120 and climbing! Never could get about 90+-. Port continued to 142-150 depending on where I measured!!! Revving it increased water flow and temps when down, and began climbing again when back at idle.

Starboard side has the small tear in the Diaphram, but it too warmed up. But only to about 120 and remained there, Probably due to that tear. I will replace that diaphram.

I dont understand the Idle air bleed relation to Water Tempatures at all yet....But Ive worked on the all week and will take any gains I can. It runs smooth at idle, little smoke and at Tempature.

 

[cfauvel]

RESOLVED???

Hmmmm....Well. For those that have followed this....I made progress. However I dont quite understand the relationship!

HOWEVER, the motor now idles really really well, and a pleasant surprise after getting it to idle.....the temps went up to NORMAL with no other cooling work!!!! Please help me to understand.

THE SCOOP:

I tried everything with the stat components. Had a OEM manual descrapency VS the BRP site diagram. But I managed (with help Cfauvel here) to verify my stat components were correct. Tonight I took them apart and back together again, after testing the vernatherms, and sealing up the cover gaskets.

Being so frustrated, I decided to leave the low temps issue alone for awhile....and look toward the rough Idle issue anyway. Holding off on swapping the VRO with a spare, I decided to go for the front 4 adjustable Idle air bleed screws.

I was surprised to find them barely 1 turn out from seated...My book calls for starting at 2 turns. With motor off I went to 2 turns, fired it up and immediately noticed a difference in smoothness and less smoke. While Running, I went an additional 1/2 turn on each--it got even better. Went to 3 turns from seated-and stopped there. I hadnt noticed how much it smoked, until alot of that went away also.

By the time I finished celebrating, I put a hand on the Heads, and could feel heat!! The IR gun showed 120 and climbing! Never could get about 90+-. Port continued to 142-150 depending on where I measured!!! Revving it increased water flow and temps when down, and began climbing again when back at idle.

Starboard side has the small tear in the Diaphram, but it too warmed up. But only to about 120 and remained there, Probably due to that tear. I will replace that diaphram.

I dont understand the Idle air bleed relation to Water Tempatures at all yet....But Ive worked on the all week and will take any gains I can. It runs smooth at idle, little smoke and at Tempature.

yay but WTF!!??

backing out the screws would make it richer....that should make it run cooler, totally confused....I hope someone chimes on and explains this to us....

 

[rothfm]

Yea, I hear ya....I'm thinking maybe its opposite, with screws in, it cuts out air entry making it richer...backing them out allows more air/leaner. Definitely quite a difference though.

Thanks for helping, very much appreciated.

 

[cfauvel]

Yea, I hear ya....I'm thinking maybe its opposite, with screws in, it cuts out air entry making it richer...backing them out allows more air/leaner. Definitely quite a difference though.

Thanks for helping, very much appreciated.

you're probably right, hence the smoke disappearing

 

[jakedaawg]

Opening an air bleed makes leanerr. Screwing an air bleed shut makes richer because you are not allowing as much air. The needle end meters air until the throttle plate passes the orifice, at that point it becomes a fuel bleed only with no air being introduced. These bleeds are not only idle bleed orifices but also transition ports or off idle ports.

 

[cfauvel]

Opening an air bleed makes leanerr. Screwing an air bleed shut makes richer because you are not allowing as much air. The needle end meters air until the throttle plate passes the orifice, at that point it becomes a fuel bleed only with no air being introduced. These bleeds are not only idle bleed orifices but also transition ports or off idle ports.

Yeah ...never saw an idle air bleed mixture screw before (especially on these plastic carbs) ....opposite from idle mixture screw seen on cars.

thoughts on the temp? I can't conceive that an overly rich motor would NOT warm up the engine, like the OP was seeing...