Idle RPM change

[Wxguru]

Took our "new to us" boar out Satirday for a spin. On muffs and the water time, idle was right around 675 rpm...it kinda idled a bit rough. And would die 1 or 2 minutes later if left idling. It also would take a few cranks to fire back up but ran great up to full throttle.

This was the first time this boat has been on the water in 2 years...so assumed it might just be cranky initially.

Filled it with 91 octane with no ethanol and added quicksilver level 2 fuel system cleaner.

Fast forward to yesterday....cranked it on muffs and fired on first turn of the key. But idle now is around 825rpm. No matter position of gear shifter.

What could cause that?

 

[Grub54891]

Model, Serial number of motor, year of boat.Thank you.

 

[Texasmark]

You cleaned out the crud and the engine runs better. Pull the cowl and look at the engines throttle linkage. Look at the arm(s) that move and on one of them you will se a spring loaded knurled (made for using your fingers to turn)screw that stops the arm(s) from moving down to the idle position. Back it off till you get back to your origianal rpms. On 90-125 hp 2 strokers the manual says with boat moving, in F gear, set to 675+/-50.....fast enough to keep running, but slow enough for smooth shifting.

 

[Wxguru]

My apologies....all that info probably would help.

1992 Crownline 196BR
5.0LX engine w/327 hours
4 BBL Rochester Carb
Alpha one Gen 2 Outdrive

Have no previous maintenance history but I am 3rd owner. First owner had for 25 years, kept dry docked in Marina when not in use. Original interior looks practically brand new still.

Not knowing maintenance history, I did the following when I bought:
New plugs (NGK), new wires
Distributor Cap and Rotor
Fresh oil change
New Fuel Filter/water separator
New Ignition Coil
Pulled lower unit-replaced oil (nearly black), new impeller

I changed wires, plugs, and ignition components due to the lope it had when idling initially. It usually was varying from 600 to 700...bouncing a bit. The plugs looked rather old and looked wet fouled (boat has been idled for a bit in driveway during some maintenance I have done). The ignition coil wire was hard to get out and had dried dielectric grease and a green copper based substance. The distributor and rotor were definitely old with corrosion going on.

I do know the carb was rebuilt at some point because paint is worn off on bolts on edges.
Timing has been done before as there is a white chalk on the plate so the numbers can be seen. (I havent checked that yet).

I just found it odd that even after the maintenance items were replaced, the idle effectively was unchanged.
I figured use the fuel cleaner. with good fuel and it might help clean up the carb.

And yesterday when I went out and fired it up...I was surprised that it fired on first crank...but as I said idling at 800-825rpm. Not a lick of hesitation at that idle. But also no change when placed in gear....forward or reverse...and in neutral. 800-825rpm across the board.

 

[Wxguru]

Motor serial and ignition coil wire end.

 

[Texasmark]

Service your outdrive gimbal and lower unit gearbox. Check your hoses between the transom bracket and the outdrive...replacement would be the best bet, regardless of what you find.

Fresh fuel and fuel system cleaned out (chemical may work). If you have a water separating fuel filter between the tank and engine, servicing would be in order. Sea Foam is a great product for bringing an old engine back to life...for sale everywhere...directions on can. I keep it in my engines.

 

[Wxguru]

Service your outdrive gimbal and lower unit gearbox. Check your hoses between the transom bracket and the outdrive...replacement would be the best bet, regardless of what you find.

Fresh fuel and fuel system cleaned out (chemical may work). If you have a water separating fuel filter between the tank and engine, servicing would be in order. Sea Foam is a great product for bringing an old engine back to life...for sale everywhere...directions on can. I keep it in my engines.

Appreciate the suggestions!
I did service lower unit and inspected hoses, bellows. Bellows I believe were done by owner before me 2 years ago. They also had new transom mount gasket done due to a leak into the bilge.
New fuel/water separator also. I took the old one of, and much to my surprise when I emptied contents into a glass jar, it was a good golden yellow. No debris and no water (let settle to make sure).
Impeller I changed didnt look very old either so kept as a spare.
Pulled prop and regressed shaft.

 

[Texasmark]

Appreciate the suggestions!
I did service lower unit and inspected hoses, bellows. Bellows I believe were done by owner before me 2 years ago. They also had new transom mount gasket done due to a leak into the bilge.
New fuel/water separator also. I took the old one of, and much to my surprise when I emptied contents into a glass jar, it was a good golden yellow. No debris and no water (let settle to make sure).
Impeller I changed didnt look very old either so kept as a spare.
Pulled prop and regressed shaft.

Lookin good.

 

[Grub54891]

I'd be replacing the plug wires also, that green substance is corrosion.

 

[Wxguru]

I'd be replacing the plug wires also, that green substance is corrosion.

Yep, I didnt like that either. The blue wires are all new. That was one of first things I changed out. I decided to order the new ignition coil after pulling the wire to it and seeing that green goo.

 

[harringtondav]

My guess is either your idle mixture screws are out of adjustment, or your carb is dirty. General idle mixture adjustment is to lightly bottom the screws and turn them back out 1+1/4 turns as a starting point. Then tweak 1/8 a turn in either direction until the idle is stable without stumbling at throttle up. Your idle rpm is good so don't change it.

You may be able to avoid a carb disassembly and cleaning by using a high quality fuel system cleaner like Red Line or another brand. Read the bottle instructions for the mix ratio for a first dose on a dirty fuel system. Then run a few tank fulls with the "maintenance" dosage.

If neither of these help, you likely need to disassemble and clean your carb. Kits are relatively inexpensive and come with cookbook instructions. It's not a complicated process. Just keep track of all parts in disassembly order.

 

[Wxguru]

Here she is out on the water....first time she was splashed in 2 years.
I did have about 8 ounces or so of water in bilge after 4 hours....dont know.if that is somewhat normal but was happy to see hardly any.

 

[Horigan]

Water in the bilge is not normal. I'd first investigate it on muffs in the driveway to determine if the water is from the cooling system, verses leaking into the boat when in the water.

 

[southkogs]

If people were getting in the water and back in the boat over that 4 hours, then I wouldn't flip over 8oz. But if not, then you do want to figure out where it's coming from. Sounds like it's slow whatever it is, so you may have to spend a buncha' time on the lake opening up the bilge and looking for the pool to form.

 

[Wxguru]

Water in the bilge is not normal. I'd first investigate it on muffs in the driveway to determine if the water is from the cooling system, verses leaking into the boat when in the water.

I have probably about an hour of running on muffs (usually 5 to 10 min at a time over last 4 weeks) and havent had any water drips.
But will take a look closer when running on the water for 20 to 30 min at a time and see if I cant spot where it might be from.
Thanks for the suggestion!

 

[Texasmark]

Other than what Southkogs said, look/feel on the inside of the transom, where the boots are attached and ensure there is no leakage there. Tilt all the way up with the boat motionless, couple of folks in the jump seats.....move the steering back and forth.