2001 3.0 200 EFI cold running problem

[dinoskeeter]

I have a newly rebuilt Mercury 200 efi (3.0) and when I leave my boathouse, I idle for about 400 yards to the river channel. I then trim in and give it gas, and the engine just bogs at about 2000 rpm for about 1/4 mile before taking off with a good holeshot. It may run a little rough for the first 15 seconds and then runs great. I can fish all day without any other problems. One of my fair boat mechanics here suggested replacing the computer, but that is an expensive guess. Got any suggestions? Thanks

 

[CharlieB]

Re: 2001 3.0 200 EFI cold running problem

Are you still running extra oil?

What spark plugs?

When it bogs, kill it, pull the plugs and see what they look like.

A TPS slightly off from perfect adjustment can run a bit rich on the low end and load up the plugs but I wouldn't change anything without looking at the plugs to get an idea if it is rich on fuel/oil.

Are the T-stats old/stuck open, making it slow to warm up?

 

[dinoskeeter]

Re: 2001 3.0 200 EFI cold running problem

Thanks for the reply. I am not running extra oil now. The plugs were replaced new with the install and I have run about 90 gal of gas. I did not know there were thermostats..that could be a real possibility. Today, I idled about a mile running my Hummingbird graph. When I finally took off...No bog at all....How do I check this as I do not know where they are.
BTW, I will have to let you know the number and type of plugs later.

 

[dinoskeeter]

Re: 2001 3.0 200 EFI cold running problem

The plugs are NGK BPZ8H-N-10
Please expand on the thermostats
It will be hard to do this as I have to have help to remove my boat from the boathouse. I will do this when the water returns back to spring level. Do you think it is possible that the ECU is bad?
Thanks

 

[CharlieB]

Re: 2001 3.0 200 EFI cold running problem

See item #37 at the top of the cyl heads
http://www.mercruiserparts.com/Show...994&bnbr=170&bdesc=CYLINDER+BLOCK+AND+END+CAP

Note that this may NOT be your particular model as I did not have the serial # to look up the correct one.

Stuck or late opening T-stats can cause the symtoms your describe. That the motor seemed to perform fine with a longer warm-up period tends to reinforce that diagnosis.

Remove the stats and test in a pan of water, measure temp as you heat the pan on the stove, the stats should begin to open 130-140 and be fully open 140-150.

Repost you findings.

 

[geno368]

Re: 2001 3.0 200 EFI cold running problem

Serial # OT390545
doesn't look like those will work?

 

[dinoskeeter]

Re: 2001 3.0 200 EFI cold running problem

I finally got the Thermostats checked...fine (keep in mind that this problem was present with 90 deg days)
I pulled the plugs and they are all consistant and non oily or wet....what next?
How do I check TPS or ECM?

 

[Faztbullet]

Re: 2001 3.0 200 EFI cold running problem

That serial number pulls up a 2.5 liter not a 3.0 liter motor.

 

[geno368]

Re: 2001 3.0 200 EFI cold running problem

You're exactly right...my bad...I was told it was a 3.0...