Need Help Merc 3.0

[Mx535]

This is going to be kind of long but I want to give all the details. I have 1998 Regal 176 SE with the merc 3.0 in it. Boat is still spotless and haven’t had issues with it in years. 2 weeks ago I went to start it and it fired right up, was a little hesitant at low speed (almost idle). The next day I start it, fires up and I let it run for a minute or 2 while waiting for someone. I ended up shutting it off and when they got there it wouldn’t start. Engine was cranking but wouldn’t fire. Checked and it had no spark. It then went completely dead all of the sudden and wouldn’t crank anymore but the trim still worked which has a different line off the battery. I ended up getting a meter and finding a 55 amp fuse that connected the battery to the alternator/starter etc that was blown so I replaced that. Took it out 3 or 4 times since without much issue other than it seems the engine is shaking bad when I fire it up (could be unrelated). Today I went to start it and started for a second and shut off. I tried again and gave it some throttle, it started ran for about 30 seconds then shut off instantly (you know not choking out like it wasn’t getting enough fuel it just **** off instant). I kept trying and it wouldn’t start, just kept cranking. It finally started and had a real rough idle for a minute or so. I pulled out of the dock and again at low speed it’s very choppy on acceleration and once in a while feels like it either starved for gas or power by cutting out. Any ideas? I’m guessing that fuze wasn’t the issue and what made it go was?

 

[alldodge]

Motor serial number ?

Shouldn't be a 55amp should be a 90amp if its the one on the starter post

 

[Mx535]

0L057558 it is the fuse on the starter lug, it’s a black square.

 

[alldodge]

Thanks for the SN, have EST ignition and Merc 2bbl carb

Check battery voltage before starting, during starting and when running. Since the fuse blew I'm wondering if the ALT is shorting out and drawing to much power

 

[Mx535]

I will check that as soon as I get it back Wednesday, appreciate the help.

is there an online vendor you recommend for replacement parts? The Marina is an hour away from me and I don’t always have time to drive. Always hesitant with Amazon

 

[alldodge]

We try to support iboats when we can, good folks just gets hard finding what you need

If you always get OEM parts there should not be an issue

 

[Mx535]

Update. I can’t find any voltage issues, pulled the boat off the water yesterday after using it all week. I pulled the distributer cap off and that looked mostly ok but there was some gunk in there.

same thing everytime I run it, it starts hard, cranks for a while before it fires up and runs really rough(whole boat shakes) for a minute or 2. Sometimes cuts out 1 or 2 times but when it’s warmed up runs fine. Puffs out dark smoke when it first starts and yesterday I noticed a film on the water after I started it. Maybe I had 2 issues going on at the same time?

 

[alldodge]

Might have 2 issues, weak spark and the carb may be flooding. Said it runs fine once warmed up, could be the choke is set to rich.

 

[Mx535]

That’s kind of what it seems like. I am even questioning the spark, I didn’t check it another guy I don’t know did (friend of a friend who was there and seemed like he knew what he was doing). After he checked it is when the fuse blew so I am wondering if he some how arched it and blew the fuse which is why he saw no spark.

stupid question, to lean it out, is it the screw on the top of the carb? Screw in or out? Do I have to worry about running it to lean?

 

[alldodge]

stupid question, to lean it out, is it the screw on the top of the carb? Screw in or out? Do I have to worry about running it to lean?

Adjustment screw only adjust the idle mix, once above 1000 or so rpm the idle circuit has no bearing on running the motor. The main and power jets in the carb is what controls the overall fuel amount.

If the idle mix screw is leaned out it will not hurt anything. The motor may not idle very well which is about the same when its to rich.

If the motor is leaned out at higher rpms (from the main jet) this can damage the motor from detonation. This is when there isn't enough fuel and the vapor ignited before spark is fired

 

[Mx535]

Makes more sense, I fire it up and it idles awful, stalls out if I don’t give it some throttle bringing it up over the 1k RPMs. It’s that first time I give it throttle that it puffs out black smoke. So it’s too rich on idle and clears out when you get off the idle circuit.

im going to try that. Thanks again!