Ok Merc issues

macojoe

macojoe

Administrator
Ok motor started perfect at the ramp, we headed out, got about 5 miles out and it started to bog down?? Then it stalled? I restarted it and it stayed running, but after I took it down from 5000 to 4500. Then it cleared up and ran fine all day.

Then as you can see in the pictures it seemed to run hot all day?? The new Tstas were opening and it was peeing but always hot? This was trolling all day at 5mph, is this normal?? Should I take the Tstas back out?

Time to go home hit the throttle and got her to 4500 hot water went away in seconds, about half way in again it started to bog down?? Never stalled but would bog up and down for the next few mies thwen it clweared up and we were home.

What we did to the motor in Juy, changed the stator, a coil, recterfier, rebuilt the fuel pump - the ck vaules, cleaned all carbs and put all new gaskets.
Stator, recterfire, coil were used parts, the rest new.

CB and Mark both think it was a fuel issue?? The gas filter is there from the beginning of the season, 40 gal gas in it from 8/1 till now and I added stabil and another 60 gal gas before we went out.

Motor sounded great at 4500 and was pushing the Ox 4 guys all gear and 110 gal gas to 23 mph at 4500. My friend Mark said it was the best sounding Merc he has ever heard!! CB and I agreed, just need to fix this stuff!!
I like to get it fixed before I put it away for the winter so there is o problems when spring comes.

So what you guys think??

Thanks!
 
MJ - I think it's bogging cause it's not getting the fuel it needs at higher RPM (above 4500). Whether it's the fuel pump, carbs, or some restriction b/w the tank or motor . . . We'll have plenty of time to go through the entire system this winter and replace/rebuild everything. Those motors run HOT at lower speeds, you can add a H20 pressure gauge and a temp gauge to ease you mind. I run snipped tstats during the warm months, so the motor runs colder and pees right away . . . but you can flood the motor when starting (as I showed you almost everytime we went out) Hopefully Spares or Ferm will come along and chime in here.
 
bigshrimpin said:
MJ - I think it's bogging cause it's not getting the fuel it needs at higher RPM (above 4500). Whether it's the fuel pump, carbs, or some restriction b/w the tank or motor . . .
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That's pretty much what I was saying. At speed I felt the primer bulb and it seemed to me that when the motor bogged, the bulb went a bit soft. Then it filled and hardened again. The only doubt I had was that it didn't seem to make a difference whether I squeezed the bulb or not. The motor would still quickly drop RPMs, then pick right up again.
 
My MERC ran just shy of 165 while trolling. At 2800 RPM's the temps would drop way down, but from 1000-2800 she ran about 160 and idle would run 145-155. Loopers need to run on the hot side at low RPM's to keep them from fouling plugs and burn the fuel. First thing is to take your filter off and drain it into a can or something and see what's in it. Also drain the float bowls on the carbs to see if some water made it into them. Did anybody try pumping the primer bulb when it would bog down? What kind of pump does that MERC have? The early MERCS had a big funky looking pump that would often fail, the later square ones are said to be ALOT more reliable.
 
if it didn't make any difference when you squezed the bulb, then push the key in to chole the motor, if it picks up, you have a fuel issue between the fuel line and the intake, if it bogs down when you push in the key switch, it sounds electrical
 
So the heat issue is normal, ok I just wanted to make sure!!

Therm, I planed on doing the filter and bowls, I am also going to replace the filter. The fuel pump is big and weird shaped so it must be the old one as you say??

Thanks spare thats easy ton do, thanks when I get it in the water thats just what I will do, if and when it bogs down again.

Ok Bs hurry up over!!:love:

Thanks guys!!
 
MJ. second what ferm said, my merc runs 15 to 20 degrees hotter when between 1500 & 2500 rpms. they really don't seem to like trolling. I'm assuming you taken the oil injection system off, if not , that might be a prob. on hitting the choke, not sure if those carbs have a butterfly or a gas pump that pumps a shot of gas to the carb. might make a difference to what spare was checking
 
Old style MERCS used the actual choke butterfly's. If it is an enricher style with the fuel solonoid, then it won't work if fuel pressure isn't present.
 
Good point Ferm, If it bogs down the engine when you push in the key switch, then you know its not fuel, if it doesn't do anything, it could still be fuel, your not getting it to the enrichener as well as the carbs. If it picks up when you hit the enrichener, then you know its down stream of the enrichener
 
Ok I bought new replacement filters today, man the racore are $$$ $20 each I bought 2

I will replace toward the end of the weekend because of the rain. I will be sure to ck to see if there is any water in the old?
 
Ok I took the filter off and there was no water at all!!

BUT what I did find was a bunch of metal shavings??? When I say a bunch ity was not loaded but there were more then just a few pieces, and how much was stuck in the filter I have no idea??

I am waiting for a friend right now and we are going to take it for a ride.

But with metal shavings in the plastic bowl that you drain, do you think it got to the motor or fuel pump, and carbs??

not sure how these filters work?
 
Well I took the boat for a long ride and still have the same issue t times??

then push the key in to chole the motor, if it picks up, you have a fuel issue between the fuel line and the intake, if it bogs down when you push in the key switch, it sounds electrical
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when I pushed the key in, it bogs down and stalls if I hold it there long enough??

I am also still worried about how hot this thing is?? Even at a 7 miletun at 4500 rpm's as soon as you slow down seconds after there is steam coming out?

Did I say I love Merc's yet today :head:
 
The steam isn't a big deal MJ, get a temp guage and check it. Anything under 170 is pretty well normal for a MERC at low RPM's. Even my EVINRUDE in 65 degree temps will have alot of steam coming off the water from the piss tube. Sounds like you need to get BS over for a ride though.

Have you had the cowlings off of the engine yet? Check it for any restrions or such in the cowling or by the carbs. You may have an air blockage to the engine causing it to run rich since you said pushing the choke bogged it down. Theres also a chance you have some trash caught in one of your needle and seats causing this since all of the debris you mentioned in your filter. How do the plugs in it look? Try running it in the water under load and shut it down while your running on plane. Then go back and pull the plugs out. This will help you to figure out if you have a cylinder loading up or not.
 
what exactly did it do today, leave the temp issues out of the description( I agree with Ferm, doesn't sound liek anything is wrong there). it doean't sound like its runnig rich, sound more like an intermittant ignition issue, but with out running it myself, it would be hard to tell
 
After finding the metal shavings in the filter I was thinking this was the problem? So I drained the gas from the filter to see if there was any water, there was none.

Took it for a ride, started right up, and we idled out of the harbor. Got pass the no wake area and opened her up, she went fine for like 2 mikles or so. Then I could feel her sputter a little and lose rpm's
At first I was thinking that maybe the shifter was backing down its self, but that was not the case.
drove out about 6 miles and it was sputtering on and off the hole way. Got out to a light house were some guys were fishing for tog, shut her down while I asked how the fishing was, They said it sucked and I wasn't missing anything!

So I started her up and she was on like a light switch and off we went. after about 1 mile we started the process all over again?? Then I remembered about the key switch, so I pushed it in and it got worse, I held a little long at one point and stalled the motor.
Started her right up and came the rest of the way sputtering all the way.

It would go again for a few seconds then it would start breaking up again, after a few min it would go good again then replete.

Thanks guys
 
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