87 Force 125 Carb Squirting Fuel/Missing Plug

[pxsp]

Hey Guys,
I have been playing with an 87 Force 125HP on my 81 Ranger for a couple of years now. It wouldn't have been my choice of power but it is what the guy who restored the boat put on it. After some new plugs/wires, a starter, fixing the tilt trim and doing the basic tuning according to the manual I have it runnign well enough to enjoy.
It now fires up on the first or second turnover even if it has been sitting for a couple of months! So I have tuned it as well as I can and even had a stainless 19 pitch mercury prop machined to fit (works great and is half the price of a force stainless prop). From my estimates though I should be able to hit at least 50-55mph in my less than 17' ranger. I seem to be missing some RPM or power at WOT though but can't confirm the rpm at WOT because of an aftermarket RPM gauge and still have not installed the pole converter so it will read right.

Anyways, the engine runs strong and really well all the way up to WOT but the last maybe 10% of WOT does not seem to create any more RPM but my fuel consumption goes CRAZY. I am getting ready for my first fishing trip in 3 months so I pulled the boat out to run it and made a discovery that might be the answer as to why i can't get past 42MPH on GPS. The engine fired on the first spin and ran smooth at idle (I love this). I let it idle for a little while until the t-stats open a little..then i run it up to about 25% in gear until i start to see the water steaming a little, this also usually long enough to get the oil residue in the carbs cleared out after it has been sitting for a wihle. I have never noticed a difference with the cowl on or off so I had it off and just happened to be watching the carbs. I run it up towards WOT briefly and fuel starts squirting out of the starboard side of both top and bottom carbs!... I cut it back and shutdown.

I start inspecting the carb and it looks like there is a brass plug missing from a fuel galley that has been machined into the side of the carb. The missing plug looks like it is where the galley comes up from maybe the bowl makes makes a 90 degree turn towards a hole at the face of the carb intake where the carb covers would mount. It looks to me like the fuel galleys may be intended to spray fuel into the carb intake at WOT but I could be wrong. If it is it is just squirting out of the side of the carb instead. From the carb intake face, the hole is about 3/16" in diameter and goes in about an inch or so, I can't see a hole all the way through to the vertical galley from the front but looking in the where the plug is missing I think I see a tiny hole going to the horizontal shaft but it may just be my eyes messing with me. I cannot get PB blaster or even a tiny wire to go through from one to the other. so maybe it is just unused on this carb.

Can anyone confirm the missing plug on the starboard side of the carbs and function of this/these fuel galleys at WOT? I know fuel should definately not be squirting out the side of my carbs. This missing fuel to the carb intake or just the missing fuel pressure because the missing plug at WOT seems to make sense for the lack of WOT performance. Maybe the leak is just not letting enough fuel to be forced through the meter rod(tubes, jets or whatever is used on these carbs). So I know about the brass meter hole for the fuel bowl and those look fin and nice and clear but what if the top and side holes for the needle valve looks like they are notcompletely sealed anymore? I know there is a lot in here but if someone can please give me some insight into these things and a good explanation of the fuel galley etc.. that would be GREAT!

 

[SkiDad]

hmmm sounds like you have a weird issue for sure - as for speed I'm not sure how much faster you will get it to go (depending on weight) - Force doesn't really have a lot of top end speed and 42 is pretty good. what is your RPM at 42. I'm sure Frank will have some helpful advice on the carbs -but if you can post a picture or 2.

 

[jerryjerry05]

Nothing in your attachment.
The 2 holes on the side?
Sounds like they are the overflow.

The floats might be stuck allowing the fuel to run out.

50-55 from a 125?? That's stretching it a bit.

Post some pics of the prop and the lower unit where they meet.
Usually anything "modified" will cost you in a different area?
You have the exhaust snout still in place?

This statement. (Anyways, the engine runs strong and really well all the way up to WOT but the last maybe 10% of WOT does not seem to create any more RPM but my fuel consumption goes CRAZY.) Sounds like the prop might be too much for the unit?
Get a Tiny Tach and install. That will give you the RPM,s you need.

Had 17p props on my boat. Wanted more!!speed, take off etc.
Changed to 19p and got more. 3mph more, fuel usage went up by 20% or so more.
Without the tach you and I are just guessing.

 

[pxsp]

Not sure what happened with the attachments but it has been fixed. Pretty sure the fuel bowl overflow and vent is on the otherside of the carbs on top of the bowl, they are little brass plugs with an air hole in them and are clear. The tach is an issue I still have yet to fix, I have one but need to install the converter so it will read correctly. The stainless prop is the exact dimensions of the aluminum prop I took off. Only the back of the prop where it meets the foot and the middle spline space had to be milled down. It even has the recess lip to fit inside the foot correctly. It is the recommended prop pitch from what I remember in the book. The engine and prop are also at the correct height in relation to the bottom of the boat at back. The exhaust tail is also in correct position.

I say 50-55 is a reasonable goal because it is a much smaller and lighter Ranger bass boat than my father's that will do 56 with 2 men and tackle.
Aside from performance that I think is lacking I am more concerned about the fuel that is squirting out of the side of my carbs at WOT.
Last night I plugged the two holes in the picture by dipping some NO. 5 lead shot into a carb sealing compound and tapping them in.
It is a nice fit and should work well in the place of the brass plugs that I would not even know where to begin looking for. I wanted to pull it out today and get my tach to work and run it to see if it made any sort of difference but it will probably be a couple of days before I have the chance to test it.

If anyone can confirm that those are indeed missing plugs first and foremost that would be great!

 

[jerryjerry05]

Ask yourself this. How would 2 carbs both the same thing suddenly be missing TWO brass plugs and fuel be pouring out the holes??
I'm pretty sure the hole on the side is the overflow.Post pics of the other side. I went out to my carb bucket and found I had sold my 125 carbs.CRS.
The front threaded hole is for a carb cover. The parts diagram calls it a choke.???
Very important to replace, if your cowl still has the foam liner still glued inside. The foam falls off and into the carb throat.

 

[pxsp]

I have been working on engines for a long time and have seen stranger things than two plugs come out at the same time. Thank you for going to look though. It may not have been all of a sudden just something I did not notice before. They could have not been staked correctly from the start, the previous owner could have put them in a cleaning vat to rebuild them (they were cleaner when i bought it) or simple hot and cold cycles over time and could have caused them to come loose. Right now it just looks like a fuel galley that was not used on this version Hopefully, someone else can confirm this for me though and that it just needs a plug.

I have looked at pictures in my manual and parts breakdowns, the grainy pic in my manual looks like there is a plug there and it is machined exactly like the two holes that do have brass plugs. There is nothing on the other side except the sealed ports for the needle valve and the small meter hole brass plug on the top back of the bowl.. this is what I would call the bowl overflow. I have already tested the float valves and they are as good as it gets. The parts breakdowns do not appear to be different for the different models of the 87' 125HP either.

Yes, there are three threaded holes in the choke for the covers but those are the threaded cast pieces at the 12, 4 and 8 O'clock positions. The one i am showing in the picture is not a threaded hole. It is at least an inch or so deep and goes back to the "fuel galley" where the plugs appear to be missing. There is no foam in my cowl and it did not come with the two covers when I bought the boat. The pictures of the covers do not appear to do anything more than that and do not have any sort of other function and I have read about a lot of people just leaving them off because the bottom one can be a pain to get off..

 

[pxsp]

Ran the engine this afternoon. Plugging the two holes on the side of the carbs had no ill effect on anything. Still fires right up and screams to WOT except WITHOUT any fuel squirting out of the sides of the carbs. The squirting fuel issue seems to be solved.
Now here is something that I have noticed since the first time I tried to tune the engine and before I noticed the carbs squirting fuel. After fixing the missing plugs it still does this.
My top carb's needle valve has always seemed to have almost no influence over how the top two cylinders are running. I have already pulled the top and bottom carb needles out and inspected them and they look fine, i have even swapped them and it made no difference.
Starting with both screws 2.5 turns out from lightly seated... i can screw the top carb's needle it all the way closed and it barely... just barely starts to cough a little bit, while screwing it all the way out has practically no effect. If I reset the top carb's needle to 2.5 turns out I can only turn the lower carb in or out about 3/4-1 turn before it starts kicking or spitting.
With the engine running at about 25% throttle and in gear if I place my hand over the top carb's intake the RPMs doesn't drop a whole lot. If I do this to the bottom carb it almost instantly loads up and starts to cut off.
Would this tend to indicate a problem with maybe the top 2 cylinder's reed valves or the recirculation system? The compression seams equal across all 4 cylinders but I would have to get a compression gauge to be sure.

 

[jerryjerry05]

Between the carbs is a black hose.
That's an equalizing pipe.
To set the carbs you should actually pinch off the hose so it doesn't feed between the carbs.
The initial setting is 1 and 1/8th out from lightly seated.
Both air screws perfectly smooth and both have a sharp point?

You need to have the motor warm, in the water and in gear.
Set at 1 and 1/8th out.
Pinch off the equalizer tube.
Start with the bottom carb.
Turn the screw in 1/8th of a turn.
Wait 10-15 seconds and then in another 1/8th turn waiting 10-15seconds between turns.
Do this until it coughs or bucks.Then out 1/2 turn.
Very important to wait the 10-15 seconds, it gives the motor time to burn the fuel at the old setting before it gets fuel at the new setting.
Repeat on the top carb.

Then remove the pincher on the tube.

If you get no reaction when you are doing the carbs then remove the plugs you installed and see if it makes a difference.
Pic of the carbs other side.

While it's running, spray some starting fluid around the base of the carbs and the intake.
If it changes anything you might have an air leak.

Also if the plugs are real dirty it helps to clean them first.
What plugs are you using?

 

[foodfisher]

http://smallengineinformation.com/?page_id=634This may help, especially the section on maintaining a fuel supply

 

[pxsp]

Between the carbs is a black hose.
That's an equalizing pipe.
To set the carbs you should actually pinch off the hose so it doesn't feed between the carbs.
The initial setting is 1 and 1/8th out from lightly seated.
Both air screws perfectly smooth and both have a sharp point?

You need to have the motor warm, in the water and in gear.
Set at 1 and 1/8th out.
Pinch off the equalizer tube.
Start with the bottom carb.
Turn the screw in 1/8th of a turn.
Wait 10-15 seconds and then in another 1/8th turn waiting 10-15seconds between turns.
Do this until it coughs or bucks.Then out 1/2 turn.
Very important to wait the 10-15 seconds, it gives the motor time to burn the fuel at the old setting before it gets fuel at the new setting.
Repeat on the top carb.

Then remove the pincher on the tube.

If you get no reaction when you are doing the carbs then remove the plugs you installed and see if it makes a difference.
Pic of the carbs other side.

While it's running, spray some starting fluid around the base of the carbs and the intake.
If it changes anything you might have an air leak.

Also if the plugs are real dirty it helps to clean them first.
What plugs are you using?

Hey jerry,
The only connection that I have between the two carbs is the fuel line on the port side. It comes up to the bottom carb with a T-fitting and then up to the top carb.
The tuning method you describe is very similar to what I do and what my Clymer shop manual says but makes no mention of pinching anything off.

Reading some other threads the idle screw not making much difference seams to point to the screws needing replaced or leaking carb gaskets as you have suggested. When I pulled the idle screws out previously they looked OK to me. I could see where they were seating but they did not appear grooved. I will have to pull them out again to look at the points again but it couldn't hurt to replace them anyway. What about their seat?

The plugs are always the first thing I check when there is an issue and I regularly pull them to check and clean if i need to. They are usually all very close to each other but they do tend to have a little wet oily carbon that wipes off with a rag and some WD-40 or PB-Blaster very easily. I do not have the plug numbers, they are Champion I think, but they are the surface discharge type that just has the little flat nub of an electrode. I have tried 2-3 of the different recommended plugs and these seam to perform the best.

I am also in the process of reinforcing the area where the hull of my rod box (no ribs) meets the top cap and resealing the whole top cap so I stop taking on water when wake hits the bottom of my rub rails in those areas on both sides of the boat. I will hopefully have some more time to play with the engine again tomorrow after I get it sealed and all riveted back together. I will post some better pics of the 2 carb-4 cylinder setup and check a few more things that have been suggested and follow up.

 

[pnwboat]

Red arrow in the picture below points to the "balance tube" or hose to pinch off that Jerry is referring to.

 

[pnwboat]

FYI Pxsp, I was cleaning out my workshop and I found an old parts carburetor with a casting date of 1989. It looks to be the same as yours. I looked at the hole that you thought might be missing a plug. The carburetor that I have does not have a plug either. Upon further investigation, that hole goes to a passage that leads right to the fuel bowl. That would lead me to believe that this is your fuel bowl vent.

On the other side of the carburetor, there is another hole with a small brass plug with a metered hole in the center of it. This hole leads to a passage going to the center pick up tube casting above where the main jet is screwed in. I believe that this is a metered jet that allows a small bit of air to be picked up and mixed with the fuel being sucked into the carburetor venturi or throat.


Carb with no plug.


Hole leads to this passage in the fuel bowl.


Small brass plug in passage that goes to the center pick up casting above where the main jet is located.


Based on what the symptoms that you describe, I would venture to say that your needle valve is not closing all the way at WOT. Could this be the reason that you are not experiencing the performance that you feel you should be seeing. Not sure about that. I can say that the only time I've heard of someone achieving numbers that you are mentioning is when Frank A. put a 125 on a 14 footer (I believe it was a 14 footer???). What ever size it was, it was small.

Getting back to your fuel squirting out, I've found that with a lot of the aftermarket parts made these days, you may have to set the float level just a tad lower than factory specs to get the needle valve to close securely and not leak.

I don't know if this helps but good luck with your efforts and keep us informed.

 

[jerryjerry05]

PNWBOAT, thanks for the pics.
That's right on the money.
The info on the aftermarket parts is right too.
Most times the carbs only need cleaning and new parts aren't needed.

 

[pxsp]

OK.. didn't remember seeing that tube on the intake but it is there, when you said that I was thinking that it was directly linking the carbs like the fuel line. I didn't have much time to play with it yesterday but enough to decide I am going to go ahead and replace a few more things for starters. The fuel lines and that carb balance tube are as hard as a rock so it wouldn't surprise me if there was even a crack in it i couldn't see. I had a hard time cutting it with dikes so there was no chance of pinching it shut to do the carb adjustment. I pulled the idle screws again and they don't appeared grooved but you can definately see where they seated. I wouldn't call the points sharp but the look just as pointy as the replacement screw pictures I have seen. I am just going to go ahead and order 2 new ones just for GP and to eliminate it as a problem. I will recheck my float settings and check for air leaks when I get some of the parts in and have time to play with it again.

Even though the spark on all 4 cylinders has always been good and never a problem I now have to replace an ignition coil since I managed to break one of the wires. The plug boots never seemed to clip on the plugs solidly and are hard and starting to get a little brittle so I was hoping I could remove it from the coil and replace the wire and boots but they are all made together. I thought it was unscrewing from the coil but I just managed to twist it of. Luckily I found a full set on Ebay for $70 shipped so i am just going to replace them all.
I need to get this thing at least running put back together.... I am dying to do some pre-spawn bass fishing! I will post back when I have made some progress..thanks all for your input.

 

[jerryjerry05]

A piece of thick paper from a box lid or similar.
I cut it in a strip about 3/4in long wide 3/8 wide and slip it in the boot.
Tightens enough to stop it slipping off.