1985 Force 85 high altitude carb jet question

[Shang]

I'm looking for any info on the jets for this motor. Carb # 581061 WE 4-1 top carb, middle and bottom carbs are # 582061 WE 4-2. Is there a difference in the carbs? I live 1 mile above sea level and just want to be sure which jets should be in it and where I might purchase them if needed. I'm also trying to find info on float drop so I can check as well. I have a manual coming later this week but sometimes they dont cover all that,

The problem I'm having is after the motor is warm and shut down, say to load a skier, it wont start again unless its choked. Then it just reaks of fuel and loads up and takes a few minutes to clears out so it wont stall upon adding throttle. When it's cold or has cooled down sufficiently it runs great, until you shut it down again. I will be going out and doing a lync sync and check timming here in the next day or two when the weather clears, then I want to turn my attention to the carbs. I will first try to set each carb starting from factory settings, 1 full turn out from closed. I know these motors are getting extremely hard to find parts for so I'm trying to stock up on parts now as well. Going to change water pump propeller and seals next.

Any help would be appreciated,
Thanks

 

[SkiDad]

what about starting it up in fast idle - pull out throttle base towards you with left hand and then push forward with right hand. It does the trick on my boat every time - if i don't do this sometimes it takes 2 tries when switching skiers.

I'm sure Frank, Jiggz or Pwnboat will be of some help on the carbs - my thought is maybe try at 3/4 turns out to compensate for your altitude. You will have to adjust your idle if you change this - make sure you idle is about 750 while in gear in the water - if that is too low that will cause your starting issues too.

PS - do you have the correct spark plugs ?

 

[Frank Acampora]

At a mile high, there is less air because of the reduced density. Water boils at a lower temperature than 212--I forget the actual numbers but most recipes will give a different cooking time for altitude.

Back to the issue: Air is the limiting factor in any internal combustion engine. The engine can only pump a finite amount (volume) of air. Because the air is less dense, for a given volume, the engine takes in less weight of air. NOW. The proper fuel/air ratio is figured by WEIGHT. Thus, at altitude in order not to run too rich, the maximum fuel flow must be reduced. Remember: A venturi will run richer with increasing air flow. THUS: the high speed jet LIMITS the fuel flow at full throttle.

NOW, to answer your question. At 5000 feet you must reduce the high speed jet(s) by three sizes. And, you must also reduce prop pitch to compensate for the reduced horsepower output.

As to your carbs, most early Force engines used three identical and identically jetted carbs. However, the carbs had different numbers because the top one had a different fuel fitting . Some Force engines did use differently jetted carbs so you need to know which one you have. I believe the we-4 carbs were jetted identically.

As an aside, the reason later Force engines used differently jetted carbs was this: The center crank counterweights are much smaller than the top and bottom. Thus the crankcase is less packed and can ingest slightly less air. A differently jetted carb was used to compensate for this slightly reduced weight of air.

You need to open the carbs and see what jet size they are because not all 85s used the same jet sizes. Then look at the big engine parts suppliers to see if they have the size you need.

My personal preference would be to contact Franz at franzmarine@aol. He knows more about Chrysler and Force engines than almost anyone and can probably tell you the jet size you need just off the top of his head. He probably will have the parts in stock.

 

[Jiggz]

If you check with Boats Dot Net, you will see a list of difference size of carb jets for your engine corresponding to different operating altitude. Technically, this is a gist of the list: 0.074"-Sea Level; 0.072- 2500~5000 feet; 0.070-5000~7500 feet and 0.068-for 7500 and up. The only problem is none of them is available anymore. But that should give you an idea what jet size you need for your operating altitude.

What puzzles me though is why the engine has a hard time starting after it's warmed up. When it should be the other way around, hard to start when cold and easier when warm. Additionally, why it starts only with choke when warm considering if you have the std size jets the engine is already running rich to start with. Your intent to do the link and synch is a good start but you should also validate the timing and check to make sure your plugs are clean and the proper ones. I prefer the NGK BUHX for this engine. If the problem persists after this initial t-shooting repost.

 

[Shang]

The boat had been maintained by a marine mechanic up until I bought it and it was owned by the same family since it was new. They were pretty meticulous about maintenance. I've tried every procedure to start it after it warms up and choking or letting it cool are the only ways to get it to start again. Spark plugs are correct ones and the carbs I adjust starting from top to bottom and each set to 1 turn out from closed. Then I lean them one at a time a listen for the motor rpm to change then go rich until it does it again then find the middle point between each. I do this to each carb 1 at a time and usually repeat 2-3 times until there is no change in the sweet spot. From what I've gathered the timing should be around 30* at neutral idle and about 28* in gear under load, does this sound correct. I know own my old V8's at this altitude they timing would be about 2* different, so instead of 4* before TDC it would be closer to 6* before TDC.

My guess with the motor not wanting to start was that it was flooded due to the amount of fuel/oil coming from exhaust and the over whelming gas odor after and during starting. I tried cranking it with full throttle until the battery died but it would only act like it wanted to start, push the key in and walla starts but very loaded up.

Another issue I have is I can't find info on this motor. Every model year chart I've found doesn't correspond with my VIN and serial 's. Model# 856X56 serial# 3722.

Frank, I get what your saying about altitude, I've flown large scale gas powered R/C model airplanes for years and altitude plays havoc on tuning at different altitudes.
Can the fuel bowls be removed with the carbs still on motor or is it batter to remove each first?

I will post pics later today when I get home because of all the variations of this motor. I always seem to get the odd balls, both women and vehicles.

Thanks for all the input and hopefully this weekend I will be able to tear into it and let you all know what I find out.

Shane

 

[Jiggz]

No Title

Based on the description of the problem you just posted, I would try to keep the idle screw at 1 turn out on all three or even at 1 1/8 out. This is the standard setting anyways from the factory. You will keep this setting until you find out what is causing the hard starting when engine is warm. Next move is to remove the carb bowls one at a time and make sure they are immaculately clean with the floats freely moving. Use carb cleaner if you must to clean all the gunk. While bowl is off, make sure you clean the idle circuit thoroughly. Use a tiny wire to make sure none if clogged.

I've attached a pic of the carb fuel ckts (high and low). Note that the idle ckt will only function if the throttle is positioned no higher than 1/8 opening. Otherwise the high speed ckt takes over. This is very important because some people try to make up for lost of idle speed by increasing the opening of the throttle thus losing the entire the idle ckts on all three carbs. The lost of idle speed control is mostly attributed either to misfiring cylinders or one of the carbs has clogged idle ckt and people tend to correct this by increasing throttle opening.

The fact that you have to choke while engine is warm or hot, tells me the carb's idle ckts are most likely not working and you are basically idling using higher throttle openings to compensate. The best indication of this is higher than normal idle engine RPM. Normal idle engine rpm (in water and not on hose) should be around 800-1100 RPM in neutral and 700-900 in gear. DOUBLE CHECK YOU DO NOT HAVE A MISFIRING OR NON-FIRING CYLINDER. For inexperienced boaters on 2 cycle engine this is quite hard to discern. But with the use of compression tester and in-line spark tester you should be able to discern. If not you can take the old method of pulling plug wires but make sure you do it very quickly as it could damage the CD mods. When you pull a plug wire and engine dies, it tells me you could have a non-firing cylinder or if there was no change in engine sound, then the wire pulled is not firing at all.

 

[Frank Acampora]

While you CAN get a 7/16 wrench on the carb bowl nuts and remove them, there is simply not enough room to remove the bowls with the carbs attached. If or when you do change jets, use a new or very good screwdriver. The jets are in tight and a poor screwdriver will ****-up the slot. I like to use the large flat blade from those combination flat and Phillips screwdrivers.

 

[SkiDad]

do you think he could have issues with puddle drains ? I haven't looked into that on my engine but it has been something in the back of my mind

 

[Shang]

Gonna try this again, everytime I try to post a pic about half way through a pop up says I'm not authorized to post, because I've been logged out. hhmmm weird..

 

[Shang]

I will start removing carbs later today as well as lower unit to change seals and impeller.

 

[Jiggz]

Looking at the position of the three throttle valves, if this is the neutral position, then I would surmised the idle screw is not set properly. The throttle valves seems to be closed all the way hence making starting very hard. With a properly set idle screw there should be some opening in each of the carb's throttle valves. Unless, these pics were taken with the control tower or bar linkage disconnected which doesn't seem like. Remember the idle screw is located at the bottom of the control or timing tower which has a 7/16" lock nut on it while the screw has a slotted pan head (unless it was already replaced). Do you happen to know what is your idle rpm?

 

[Frank Acampora]

In one of your photos I can see that the bottom spring loaded quick-connect fitting (throttle) is not pulled out about 3/16 inch. the engine is in neutral because the neutral interlock switch is depressed. In neutral the large spring loaded quick-connect must have the center slug pulled out about 3/16 inch. This allows the engine to shift into gear BEFORE the throttles start to open. Go to youtube and type in Frank Acampora videos. Click on the video titled synchronizing carbs and timing.

 

[SkiDad]

Those are some nice pictures you took and a nice clean engine!

 

[Jiggz]

Other thing I noticed is the alignment of the eccentric screw with the throttle cam. As previously mentioned, do the link and synch and then repost your results.

 

[Shang]

RPM at sustained idle is around 800-850, after clearing out motor, but only lasts about 10-15 secs. before it starts loading up again and idle drops off quite a bit. Controls were indeed in neutral at all times in photo. All my carb parts, including jets, are on their way. When they get here I will go through each carb then do the link n sync as in the video. Great video by the way, I actually found it a few days ago, great info.
On the neutral interlock switch, I was curious about its position. On an Evinrude I had it was in the middle of the tab that depresses it, on this it is towards one end. I do shift into gear firmly but still tend to get that dredged clacking of the gears. Would this have anything to do with that. I will post a better pic in a few, have another of a part that fell off when I lowered motor after removing lower unit. Can't find it in the manual anywhere

 

[Shang]

This looks like it sat on top of the splines due to the spline marks on the inside of the rubber sleeve, not sure about the ring though..

 

[Shang]

Got the pump kit but wanted to be sure before I put it together.

 

[Jiggz]

That is the spline seal and its retainer. The retainer goes in first with its shoulders facing up and then the rubber boot seal with the long end seating against the retainer.

 

[Shang]

Ok so I'm ready to put the lower end on now, just want to be sure this is how the shafts seal goes on. Also wondering if there is anything else that goes in their I may have missed. The rubber seal goes down in the ring like in the picture?

 

[Shang]

At a mile high, there is less air because of the reduced density. Water boils at a lower temperature than 212--I forget the actual numbers but most recipes will give a different cooking time for altitude.

Back to the issue: Air is the limiting factor in any internal combustion engine. The engine can only pump a finite amount (volume) of air. Because the air is less dense, for a given volume, the engine takes in less weight of air. NOW. The proper fuel/air ratio is figured by WEIGHT. Thus, at altitude in order not to run too rich, the maximum fuel flow must be reduced. Remember: A venturi will run richer with increasing air flow. THUS: the high speed jet LIMITS the fuel flow at full throttle.

NOW, to answer your question. At 5000 feet you must reduce the high speed jet(s) by three sizes. And, you must also reduce prop pitch to compensate for the reduced horsepower output.

As to your carbs, most early Force engines used three identical and identically jetted carbs. However, the carbs had different numbers because the top one had a different fuel fitting . Some Force engines did use differently jetted carbs so you need to know which one you have. I believe the we-4 carbs were jetted identically.

As an aside, the reason later Force engines used differently jetted carbs was this: The center crank counterweights are much smaller than the top and bottom. Thus the crankcase is less packed and can ingest slightly less air. A differently jetted carb was used to compensate for this slightly reduced weight of air.

You need to open the carbs and see what jet size they are because not all 85s used the same jet sizes. Then look at the big engine parts suppliers to see if they have the size you need.

My personal preference would be to contact Franz at franzmarine@aol. He knows more about Chrysler and Force engines than almost anyone and can probably tell you the jet size you need just off the top of his head. He probably will have the parts in stock.

Frank, I watched your video on the sinking of the carbs in the timing and it was spot on everything on Mine pretty good. I did change the Jets from .050 to .070 and the float on the bottom carb was way off. The top of the float was completely visible when you help the carb upside down and the float was rested. With changing the floats do I need to change the needles as well?