2005 Merc3 Liter: Won't idle, tach doesn't work, tilt gauge not working

[cheapthrills]

Sorry to combine all three probs, but thought one or more may be related. Just bought a 2005 Bayliner w/3 liter Alpha one power. Boat is a BankAmerica repo. Dealer I bought it from has been cleaning it up and fixing a few things. Sea trialed it yesterday and have three issues.
1) The enigne won't idle. Runs great at off idle to full throttle but will not idle. When drive is placed in neutral at idle, engine dies. When drive is in gear and throttle is dropped to idle, engine dies. The slower the engine runs, the rougher it runs. Hard to restart but will restart. Carb was rebuilt by dealer (used boat seller, not Merc dealer) The carb was really gummed up before so I suspec that it had been sitting on traler for some time(no idea how long).
Boat shows no outward signs of abuse and outdrive is in perfect condition with no external wear or paint dings at all. Prop shows very little wear.

2) Tach doesn't work. No twitch, no movement of needle at all.

3) Tilt gauge doesn't work. Tilt does work, both up and down. Noticed that while I was running it, gauge suddenly went from full down to full up and then back again. Happened twice, otherwise didn't move.

Dealer is going to swap out carb and "check" wiring. Any help is greatly appreciated.

 

[achris]

Re: 2005 Merc3 Liter: Won't idle, tach doesn't work, tilt gauge not working

Poor idle sounds like a mixture problem.
Tacho could be wiring or the instrument itself.
Trim guage sounds like the sender. One SoB of a job to replace, and expensive for the parts.

Good luck.

Chris..........

 

[krisnowicki]

Re: 2005 Merc3 Liter: Won't idle, tach doesn't work, tilt gauge not working

A lot of people just forget about fixing the trim gauge ... it is kinda of useless because most times it wont reflect your needs and you have to learn each boats trim "sweet spots". If it were my boat I would focus on the other two problems.

 

[Don S]

Re: 2005 Merc3 Liter: Won't idle, tach doesn't work, tilt gauge not working

Your idle is probably still due to a plugged carb. Check the mixture screw and see if it still has the tamper proof seal on it. IF it does, then it was probably never removed and may be plugged up.

 

[cheapthrills]

Re: 2005 Merc3 Liter: Won't idle, tach doesn't work, tilt gauge not working

Thanx for the info. Dealer replaced the carb and she now runs great!

Still no tach or trim gauge but she idles fine.

Does it matter which end I start at when I trouble shoot the gauges? Most likely, I'll lift the dash out and start at the gauge ends and track the wiring and connectors back to the engine/outdrive.

Any suggestions on troubleshooting the trim guage and tach are much appreciated.

 

[Fishermark]

Re: 2005 Merc3 Liter: Won't idle, tach doesn't work, tilt gauge not working

A quick and easy first step for the tach is to unplug the main engine harness plug (the big round plug that the boat wiring plugs into). Check the condition of the contact ends. If they are corroded, that's a common area of concern. If they look good, plug it back in and wiggle it some to make sure it is in good and try it again. If that doesn't solve it... then you are left with tracking it down from there.

 

[nlott]

Re: 2005 Merc3 Liter: Won't idle, tach doesn't work, tilt gauge not working

I agree that was the problem with my trim gauge. You can check for continuity before and after the main harness using a multimeter, also test for continuity from the sender to the sender wire on the gauge. Sender wire should have an increase in resistance on an ohm meter when you trim up and a decrease down to nearly nothing while trimmed down. This will be a steady change. No crazy rapid up and down fluctuation. It will stay at a steady reading once the sender remains still.