Repirts, AKA Christian's Dad

I'm having trouble with the 175 merc stalling. When I go from slow to accelerate, it will sometimes dies. Changed the plugs and that improved things alot but not completely. At the same time changed the water separator filter and replaced a leaking priming bulb but the new one takes forever to fill and seems to be pumping alot of air. Maybe I just answered my own question. I'll check for a loose connection that is s#^&#^&#^&#^&#^&g air.

Tomorrow night I'll:

1) Check for air leaks in fuel lines.
2) Decarb and clean carbs
3) Replace the New bulb.
4) Replace the on engine fuel filter

Can anyone think of anything I'm missing.

Thanks

Hey Repirts, as I mentioned on the other site, make sure the checkvalve on the bulb is working and also make sure the flow arrow is facing the right direction.
Definately sounds like a loose connection somewhere.

BigBo, Thanks for the help.

I'll check for leaks tomorrow night. The arrow is pointing to the engine. I don't think the check valve is working.

also check your idle speed... it could be a little on the low side of things.

if the check valve isn't working right on the fuel line, it'll cause those types of problems too (fuel starvation) how is the hose itself from the tank to the bulb to the engine?
those crack over time etc.

high grade gas that seemed to be my problem I started putting super and I put a can of dry gas in there and let it warm up good before heading out and that cured my problem!!

Repirts your check list looks good, you might as well check the fuel pump while your in there too, they're known to wear out. I had the same issue with stalling going from neutral to fwd with my motor, I never solved it, but to get around it, I goosed the throttle fwd and then back a bit when I got underway (give the folks onboard a heads up), this gave the motor the gas it needed to keep running.
You might also want to try running on an portable tank to rule out any issues with your gas tanks connections.
Another thing I remember is my motor would always run like a top in the driveway, but the quirky things happend when it was in the water under load.
Good luck, these problems are a nuisance, but when the sh&% hits the fan on the water, you are much more prepared.

Sounds like she is starving for fuel, look for a restriction somewhere or replace fuel pump.

Had a problem with a motor (Johnson 200 HP) that ran great out of the water with a hose attached... As soon as I put it in the water and put it in gear it would stall. After I checked all of the things you mentioned, I took it to the dealer. Turned out the shift interrupt switch was bad... The switch momentary cuts out 3 of the 6 cylinders when shifting... With the bad switch, 3 of the cylinders were never firing. I thought I had a fuel problem and to this day it still blows my mind that the motor wasn't running rough... Wish I would have broken out the timing light to verify all cylinders were working...Would have save me some $$$ on repairs.

Accelerator pump? I only had a Merc for 22 hrs. and that was enough for me :)

Monday night Christian and I worked on the boat.

Changed all fuel lines including the bulb
made sure there were no air leaks

new in-line fuel filter

decarbed engine

cleaned plugs, they only had a couple of hours on them and looked good but i was already greasey so why not

Runs much better now but I think I still hear a miss at slow idle that smooths out when idle speed increased. The wires look good but you never know. Next I'll try to find the missing cylinder.

I'll be running it in the water thursday night.

On the whole I think I have made pretty good progress.

By the way, thanks to the guys at Town river Marina in the Team Sea Monkey T shirts for their advice the other night. I don't understand all the talk about Sea Monkeys must die!

PS I'm sure team Ave Maria would have been just as much help.

I don't know much about your situation i.e. is this problem new to you, or is the motor new to you, etc.
But the symptom you describe could also be what they call the sync n link, especially if someone has been screwing around with the linkage at all.
Basically what it is is the setup of the linkage so that the timer base advnces the spark correctly as the carburators open, I had that problem on my Evinrude 225 and I'm not sure how Merc does it exactly. It usually involves lining up certain referance marks and it normally doesn't change unless someone removes or adjusts the linkage or spark advance, so if that could have happened it's a place to look.Best bet is to get a manual and follow the procedure, it's always good to get a manual anyway.
If you're sure this is a new problem and noone has touched the linkage, I would guess carbs,
Bill

OK, this is really starting to p*ss me off.

Took the boat out last night. It coughed a little when first started but as it warmed up it smoothed out pretty well. Later it died again on acceleration from neutral idle. Runs pretty good at idle and very good at speed. It only died once but that was almost enough. Both batteries were almost dead after cranking only a couple of times. I knew that one had a bad cell but I thought the other one was ok.

My question- when running my ammeter shows just above 12A on one battery and just under on the 2nd. Does this mean that the batteries aren't charging or that the motor isn't charging the batteries? Since the boat is new to me I wasn't sure of age but found label on Battery. They are 3 years old.

I figure that the best solution is to replace them both. One with a starting battery and the other with a combo deep discharge/starting.

If I get good cranking batteries, I can live with the occassional stall until i either figure it out or give up and take it to a mechanic.

PS. As far as speed is concerned, the 175 Merc pushes this boat, a Wellcraft V20, faster than anyone really needs to go.

Repirts

Repirts If your ammeter says 12 amps your charging system is fine. If by chance it is a volt meter your in trouble.make sure all your connections are clean and tight. With 2 batteries you should be able to crank for a long time. As far as the stalling. Make sure your fuel is fresh and moisture free. If it's not run the tank down, and live with the stalling till you get fresh fuel. If your fuel is good.Start with a compression test, before you start chasing everything else. A 175 is mabey a little big,and doesn't get run hard, like it should, once in a while.I think one heat range hotter on the spark plugs wouldn't hurt. Good luck

NEXT2NUN,

Can you explain what you mean by trouble if 12 volts not amps. trouble with charging system or trouble with batteries?

Thanks

Christian If you have a volt meter it should read around 14 volts (14.7)with the engine running, if not you either have a charging system problem, or batteries that refuse to take a charge(bad cells).If you have an amp meter 12 amps is ok,that should be about max output. But your battery is getting low. I would get rid of both batteries and replace with one good quality marine battery.One is plenty for a day boat.

NEXT2NUN,

Thanks for the explanation.

When I bought the boat in May, the batteries were dead so I had them charged at a service station. At that time the mechanic said that one battery didn't test very good but that the other was ok. Since they are both 3 years old, they would need replacing soon anyway and since I'm already wired for two, I might as well replace both. Also, my teen age son will be taking the boat out, so I like the extra insurance of the second battery. After all if I was interested in saving any money would I have bought a boat?

If that doesn't solve the problem, I'll look at the charging system.

Repirts (AKA) Christians Dad

Hey Christian or Repirts. In reading through your problems again, this is starting to jar something in my memory from a similar problem I had years ago. At the time, I also could have sworn that I had a fuel problem too. Rebuilt fuel pump, carbs, fuel line, filters, the works. Problem still didn't go away. In the end, it turned out to be the magneto not delivering enough power to all cylinders. I don't remember the procedure to check with a multimeter but it's spelled out very well in the service manuals. Merc's were notorious for magneto problems in a motor of that vintage. At the time it was about a $100.00 fix and didn't take too long to replace. Takes longer to remove the flywheel than anything else.
I'm not saying this is your problem, but you might want to check it out. And, N2N is correct on the voltage readings.

Spent the $$ on new batteries. Volts now reading about 14 on both. Also cranks alot better. Getting tired of trying to figure out the stalling. Having mechanic look at it next week.