update still problems merc 140

[geb]

Well, I've replaced the fuel pump and replaced the #6 coil to the motor and I still have a problem. WOT should be between 5300 and 5800 rpms, I'm only getting 4200-4500 rpms. It still bogs down coming out of the hole and will not plane out without a very slow increase of the throttle. I had my buddy with me to test it out and I've noticed that when either one of us sat at the bow of the boat it seemed to work less to get to plane. It's only a 15' 6" boat and it shouldn't be that heavy. It has been covered with no leaks for several years so my foam is fairly dry. I've got really, really good spark to the plugs...arm was a bit tender after disconnecting spark plugs to locate a cylinder not firing while running it under load and idle. I'm fixing to do the carb test (spraying mix into carbs while running to see if maybe I have plugged mid to high range in carb?) Then I'm going to take the carbs back off and soak them in gasoline overnight to see if I may loosen up any buildup that may or may not be present. So, does anyone have any ideas or other suggestions for me to try out? Also, I changed out the plug to #6 to make sure I wasn't taking any water in the cylinder and I'm pretty sure I'm not. The plugs are somewhat lightly fouled. I believe I'm going to go ahead and get another set of plugs just to rule that out as well. I'll be taking it back out to the water tomorrow to test what I will have done today. Any help is greatly appreciated!

geb

stator -------check
trigger -------check
fuel pump ----check
coils --------check
switchbox ----can't confirm unless all firing means all good even at WOT
carbs --------recleaning tonight
battery ------it's a deep cycle battery marine...will be getting starting one soon
fuel tank -----check
water sep ----check and new to boat
water pump --check
prop ---------check no wear and tear at all and wasn't a problem before (reached at least 5500 rpms in past)
lower unit ----check new lube
control box ---check (only goes to 9:00 but adjusted for full carb open at WOT)
tachometer ---check (I believe it is showing correct)
speedometer --check (unplugged the pin hole on leading edge of LU) reached 45 mph

 

[Silvertip]

Re: update still problems merc 140

On your checklist for the Control Box you said only goes to 9:00 o'clock but adjusted for full open at WOT. What went to 9:00 o'clock. If you are referring to the butterflies in the carb throat, they should only open to 9:00 (perfectly horizontal in the carb bore. If they are less than that, they are not opening far enough. If they open farther than that they are obviously open too far and begining to choke off air again causing a rich mixture.

 

[geb]

Re: update still problems merc 140

the control box shifter...where the key is.. only goes to 9:00...at which time carbs are open like this " | ". I just now carb tested in idle with the spray mix and carbs didn't increase the rpm, it seemed to want to slow it down. I'm not going to be able to test that spray mix today at WOT, so I'll test that tomorrow on the water. I'm going to go ahead and check the line to the tank that is the overflow or vent line? See if it's clogged in some way.

geb

the only thing I haven't tried with the fuel tank is attach a portable one to see if I have the same problems...may have to just break down and go buy that hook up to see???

 

[Chris1956]

Re: update still problems merc 140

Geb, We need to find out if it is a over prop issue, or a total power issue.

What kind and pitch prop do you have? Do you have power trim? If not, what hole is the tilt pin set into.

OK, what is the comppression readings on all six cylinders?

 

[Scaaty]

Re: update still problems merc 140

Yep, pull the prop nut, look for the numbers on the hub..give us the last 2 numbers, and number of blades

 

[geb]

Re: update still problems merc 140

compression 120-125 across all 6 cylinders

3 blade prop 12 3/4 x 21P

also power tilt and trim

 

[geb]

Re: update still problems merc 140

carbs are soaking in gasoline at this time till tomorrow afternoon. I pulled the fuel connector off...attached to the base cowl. It's the part that the bulb end would twist and plug into. I found some rust in it at the spring...going to see if I can find a replacement (female end) for it. Couldn't hurt, and I'm quite sure it wouldn't be detrimental to what I'm trying to get fixed! Thanks

geb

 

[geb]

Re: update still problems merc 140

Ok here's one for you guys. The pic is from my seloc manual. I've added to it. The copy of base plate on far left is my actual plate view from plate to gasket to pulse chamber. The 2nd copy from left is from my actual plate view from plate to gasket to engine block. The actual gasket that I just took off of that plate between plate and pulse chamber is in the photo to the very far right, that shows to be the correct gasket for the plate view that the seloc manual shows on the 3rd from left pic (actual book photo). The used gasket is what I got with a fuel pump rebuild for my fuel pump from local dealer, I didn't realize the difference because picture showed that gasket...I didn't pay attention to the base plate itself Well the fuel pump kit that I got in the mail yesterday had the correct gasket that matches the base plate to pulse chamber (it looks like the 2nd from left pic of plate exactly). So I have rebuilt the fuel pump again with correct gaskets, the carbs are currently soaking and will be ready to be put on tomorrow and I will be hitting the water just after 5pm, I will let you guys know how it goes when I return. My main question if it's not obvious, is do you think it matters that the gasket that was on it (far right of photo) will have caused the problem I have been having???? Thoughts?

Thanks

geb

 

[Chris1956]

Re: update still problems merc 140

Geb, It is hard to tell if your fuelpump is working correctly by the picture of a gasket. My '77 Merc 1500 had quite different fuel pump gaskets, BTW

Pump the primer bulb when the motor is at high speed and if the revs increase, the fuel pump or tank vent or fuel line is faulty. My experience has been that the fuel pumps are just barely adequate, so you may get lucky....

 

[geb]

Re: update still problems merc 140

Thanks chris. maybe I'll get lucky. I've done the bulb test at wot and idle with no change...solid bulb. Maybe the fact that the used gasket in the picture being the wrong gasket may make a difference since I have a different base plate than what the book shows. I now have the correct gasket in its place, so I'll let you know this evening.

geb

also, is there any particular grade of fuel I should be using? I started with low 87 octane..now I'm going to try mid 89 octane today.

 

[geb]

Re: update still problems merc 140

Well the pump gasket didn't make too much of a difference...a little different but not the cure. Reached 45 almost 50 mph. I can't really say if water is getting to number 6 to cause any problem because it is by no means milky when I pull the plug. What i do have is wet and black oily deposits, on most all plugs. When I give it full throttle it bogs and chokes, but more fuel doesn't help. So I've ruled out fuel problem, fuel pump, coil, stator, trigger, even switchboxes. What would cause the somewhat heavy black oily deposit on the plugs? Bad rings? Am I looking at breaking down the motor again and replacing them rings again? It's been 6 or so years since that was done, But I haven't put 30 hours on it since I've owned it. If I have passenger and shift them to the front of the boat it will finally plane out. Bulb is nice and firm. Spraying fuel mix doesn't show any problems with carbs. I'm pretty much finished taking it back to the lake for the season. Unless you guys can think of something else then I will probably break it down this winter and do new rings and whatnot...I can't for the life of me figure out any reason for the problems...maybe I'll disconnect the water separator and see it that has any result...I've done just about everything else there is to do, and that is a new addition that I put on. Another symptom that I failed to mention is that every once in a while the motor will make a loud bump or burp while in neutral. Sounds like an internal burp not a backfire...It is really a jarring jolt, but then back to idleing normal. I have no problem cranking and idling and no wake...It's just coming out of the hole and my WOT is slower than it should be. Grasping at straws now...

geb

 

[Chris1956]

Re: update still problems merc 140

Geb, If you have the compression you posted in this thread, you needent replace the rings. It will not have any benefit. Your compression is better than fine.

If num 6 plug has oil on it, it probably doesn't have water intrusion. The water ususally steam-cleans the plug to look like new. If the plugs are dirty after a high speed run, your floats may be set too high or the inlet needles leaking. Do you see any leaks from the carbs at idle?

I would definately test without the water seperator. Straight one piece fuel line if possible, to eliminate it as an issue.

I would swap out the prop for a 19" pitch. It may make the boat a screamer, versus a cryer. Those motors loose a lot of performance if the prop pitch is just a bit too high.

 

[geb]

Re: update still problems merc 140

well that's good about the rings, I was just grasping at straws...I've had good compression, thought the oily mixes on the plugs from --aah nevermind, I understand you, comp good = rings good. I thought I might have had a water problem but that didn't pan out

the pic is what my carb float and inlet needle look like...So how do I adjust the float? There is a really small spring on top of float and the inlet needle tip appears fine...I replaced the small metal washer with the gasket rebuild...should I have replaced needle and jets?

I just recently added the water separator before I actually took the boat out to see if it would run since the timing was finally set...I'll try and locate some more fuel line to reconnect--where's a good place to get some fuel line on the cheap?

As for the prop I'll go ahead and see if I can locate a 19" prop locally...I saw in recent thread about possible spun prop...is it possible for partial prop failure?? struggle under heavest load but then cruise on plane (although not at full potential (5300-5800 rpms as opposed to the 4200-4500 rpms now)--I've had the boat to 60 to 65 mph at one time till I blew out the #2 piston 6yrs ago before doing a proper clean and check of the motor, I wasn't as educated about these motors at the time )?

Thanks for the advise and input, as for the carb leaking. No leaks. Plugs just covered in heavy oily blackness on the plugs.

geb

 

[Chris1956]

Re: update still problems merc 140

There are two settings for the float height. Invert the carb bowl cover. The top of the upper lever should be straight across, parallel with the cover. Bend the lower lever to achieve this.

Now turn the cover over. The bottom lever (same as the top lever when inverted) should hang down, and the space between the two levers should be 1/4". Bend the lower lever to achieve this. The first adjustment is the most important.

One more thing. The original carb inlet needles were steel and the seats were brass with a rubber insert. These were superceeded to steel needles with neopreme tip and all brass seats. Also the floats were superseeded from hard foam to hard hollow plastic. if you have the old stuff, you might replace it.

 

[geb]

Re: update still problems merc 140

Ok, when I get home this evening I'll try the adjustment that you speak of. The floats are updated platic and the needles are shiny silver and I believe black neoprene...I'm thinking they were updated with the floats 6yrs ago during my original rebuild. With the cap sitting correctly the top float lever (one that has contact with inlet needle) is straight with a u at the end..the u has contact with the bottom float lever, which is straight with the end having beveled edges that contacts the spring in the float...you're saying that I should work on adjusting the lower float lever to lower the float inthe bowl...and just making sure you did understand I don't have any fuel coming from the overflow (bowl vent?)

geb

 

[Chris1956]

Re: update still problems merc 140

Geb, If the lever is straight across,you are likely OK. Reassemble the carbs and pump the primer bulb to see if you can make the carbs bowl leak. If you pump it a bit, and it doesn't leak, Your are OK.

 

[geb]

Re: update still problems merc 140

Ok folks riddle me this...what say someone (yours truely) had the tdc off, o about 4 degrees? Say what I thought was tdc was actually 4 btdc...that inturn made my first p/u to be 8 btdc...and that inturn made my max advance about 12 btdc. Would that explain why the problems I've been having? Struggling between 1st p/u to max advance was rough ride but when I got it on plane doing 45mph showing WOT...the spark wasn't firing at max advance, but 12 btdc...therefore causing it to actually overload on fuel and, thus making my plugs look so fouled with fuel/oil mix. It did run like a top when it did get on plane, but it would only go to about 45mph and no more. It wasn't drowning in fuel with the carbs open and 12btdc, so it would run pretty well at 45mph. Ok, I know that was a bit wordy and probably hard to understand...but after extensive studying of this site I decided today that I would just start back at the beginning...reset tdc and timing...I used a screwdriver this time, instead of my shoddy dial indicator, to actually feel the difference in movement on the piston head. After back and forth a few time with the rotation I determined my correct tdc. I then took a look at my pointer...guess what? it wasn't actually at 0, but rather at 4btdc. So I reset my pointer and proceeded to check and reset the 1st p/u and lo and behold it was actually about 8btdc, reset to 4btdc. I then proceeded to check and reset max advance, and it was 12btdc...reset to 21btdc. Now tomorrow evening when I get off at 1800 I'm going to take the boat back out and see if having the correct time makes any difference whatsoever. I'm hoping that your responses will echo what I've determined to be the ultimate problem with this old motor! Responses welcome and begged for!! I'll also let you guys know tomorrow evening how it went...Thanks a million for all your knowledge!!!

geb

ps---goes to show how a few degrees can make a difference in the life or death of our old inlines!!! because I was just about ready to drop anchor with this old gal at the bottom of my local fishing hole!!!

 

[Chris1956]

Re: update still problems merc 140

Geb, Your logic is flawed, unless you meant that your TDC was actually 4 degrees ATDC. Then your logic works.

You should really set TDC at the .464" mark. It will remove the varience that setting TDC at TDC introduces.

I use my caliper which can measure depth to set the .464". Set the flywheel to TDC anyway you can. Measure the depth of the spark plug hole to top of piston. Add .464 to that measurement and back off the flywheel until you measure that distance. Set the dial pointer to .464", and you are done.

 

[geb]

Re: update still problems merc 140

Chris, I understand what you are saying...my problem is that I don't know what .464 is on my dial indicator. I have the .464 mark on the flywheel, but I haven't set the point to it. I set the pointer to 0 on the label. This timing pointer is what has me totally confused. Just so I'm understanding correctly. I find the tdc with whatever (screwdriver), set my dial indicator to 0 at that time or what? I'm having a real problem wrapping my head around the measurement part. I set to zero then CCW or CW turn the flywheel till the dial indicator shows .464 (which I don't know where is). That should put the .464 decal in the area of my pointer and at that time I aim the pointer to the .464? This is what is confusing me. As it is my pointer is aimed at the 0 for what I believe is tdc and from there I've given 1st p/u and max advance adjustments. I have no problem trying the dial indicator again, but could you point out to me what .464 would be on the picture I've attached? Thanks, and there is no telling what my time was set too...btdc or atdc, I'm just that clueless on the pointer setting.

geb

 

[Chris1956]

Re: update still problems merc 140

.464 is nearly 1/2 an inch. Set your dial indicator to zero and then extend the pointer intil it reaches 1/2 an inch. Now you should be at something marked .500 or so. Now you should be able to find .464.