Advice on cold starting merc 3.0 Litre (140hp)

[camelot10]

I have a 1995 merc 3.0 Litre (140 hp) inboard. Our water temperatue in Canada is just above freezing but ice is out so I thought my son and I would try early pike.
The 3.0 L is always hard to start when cold I pump a few times then as it turns over I start pumping and usually it eventually goes. Let it warm up 10-20 minutes and we are good for the day.
This morning it was very close to running but not quite. Of course I ran the battery down and brought it home. I'll start it with the muffs this afternoon and it will start and run fine.
In the summer it starts and runs perfectly.
What the heck am I doing wrong?

Thanks

 

[Don S]

Re: Advice on cold starting merc 3.0 Litre (140hp)

Is the choke adjusted properly?
Is the accelerator pump in the carb actually pumping fuel when you pump the throttle?
When was the last full tuneup and compression check?

 

[camelot10]

Re: Advice on cold starting merc 3.0 Litre (140hp)

Yes the choke works and the accelerator pump pumps fuel. I have had the boat for 4 years now and have always had a hard time starting in cold water. I probably start it hundreds of times a year throughout the summer never an issue.
Even cold days once it is warmed up it will start fine it is just the first start on a cold morning.
I will try to run the boat for 10 minutes on the muffs before we head to the lake to see if it makes any difference.

No I haven't had compression tests but it works perfectly each year except cold mornings.

I do have one more question though. My alternator belt is in horrible shape and it is due to the fact that the alternator pulley has some rusty spots and has chewed the belt. Can I simply undo the motor mount at the front of the engine and jack the motor up just enough to slip the belt under? I will not overlift but I don't see any other way.

Thanks

 

[Don S]

Re: Advice on cold starting merc 3.0 Litre (140hp)

4 years is a long time in a boat. Give it a full tuneup.

You need to clean the rust off the pulleys and repaint. Then let it set for a couple of days before putting the belt back on. Gives the paint longer time to fully cure. No need to jack the engine up, and not something you would want to do with the drive on.
You do pull the drive yearly to grease the coupler splines don't you?

Here is how you change the belt.

 

[camelot10]

Re: Advice on cold starting merc 3.0 Litre (140hp)

That is great information. Thanks so much.
I don't actually grease these splines, would you have a diagram as well.

Thanks

Russ

 

[Don S]

Re: Advice on cold starting merc 3.0 Litre (140hp)

I don't actually grease these splines, would you have a diagram as well.

Just noticed you have a 95 so it's a Gen II drive and you should be able to grease the spline from the inside of the boat, There are a coupler of zirks on the nose of the coupler where the drive shaft come thru from the drive.
The drive still needs to come off to check engine alignment and to make sure you have no leaks. It's preventive maintenance and it sounds like you might not be doing much in the way of Preventive Maintenance.

Here is a link to an OEM owners manual from 2000. Same info as for 95. http://www.boatfix.com/merc/Owner/owncov.pdf

You also might want to visit the stickies at the top of this forum. Lots of Merc info in them.

 

[elkhunter338]

Re: Advice on cold starting merc 3.0 Litre (140hp)

My 140 after it sits takes some cranking to start, but if I put about a tablespoon or two of gas down the carb it fires right up.
This is only after it sits for awhile (weeks).
Is there a check valve in the fuel pump that prevents the fuel from draining from the carb line?
What you describe sounds like a fuel problem after it sits.
Once it starts cold, can you immediately shut it off and it restarts good?

 

[Don S]

Re: Advice on cold starting merc 3.0 Litre (140hp)

Is there a check valve in the fuel pump that prevents the fuel from draining from the carb line?

Fuel comes into the carb from the top, how is the gas going to jump up into the needle valve to get back to the pump. It can't.
The fuel either leaks out of the carb, or you have something else wrong.

Do you use the throttle only position and pump the throttle a couple times and giving some throttle while cranking?

 

[camelot10]

Re: Advice on cold starting merc 3.0 Litre (140hp)

Ok here is my plan of attack. I've read up on the electric choke and I think I will turn it to the right just a little to increase choke. I will start the boat in my driveway for 10 minutes before I go until the weather warms up.
Thanks to Don I located the grease nipple for the spline and will give a few pumps and I've studied out how to replace the alternator belt and will do that tomorrow as well.
As a precaution I am going to use a jack under the engine just to support the motor when the spacer is removed.
Other than that the pike and eventually bass won't stand a chance.

I very much appreciate the help and guidance and feel much better knowing I have a forum where people are willing to offer their wisdom. I feel a little guilty as my wisdom can't offer any serious guidance.