Best way to start a motor that has been sitting for a while

[wingtime]

OK here's the drill.  I picked up a little jet boat that has a Mercury 175 HP sport jet in it.  It is basically a 2.5L Merc power head mounted on a inboard jet pump.  It has been sitting for a few years and I plan on trying to start it to see if the thing runs or not.  I have turned the flywheel by hand a bit to confirm the motor is not seized (good sign).  I know the fuel system has to be cleaned out so I'm going to hook up a tank of fresh premixed fuel.  Remove the spark plugs and spray either fogging fluid or squirt 2 stroke oil in each cylinder.  Remove the attenuator to inspect the carbs and intake for debris and critters.  Spray more fogging oil in the intake. Turn the motor over by hand.  Reinstall the spark plugs, cross my fingers, and try to start it.   Did I miss anything?  Should I check the oil pump drive shaft to make sure it is not stuck?

[John Jones]

I'm not familiar with the Merc oil pump system but the rest sounds good.  If you are going to use premix then I would think you will be just fine.  (I did NOT stay in a hotel last night.  ;)  )

[fitz73222]

You're right on track Wingtime. By the looks of that boat its been sitting a long time! (years) The oil pump will be fine. The enemy is internal rust of the bearing surfaces from lack of adequate storage oil. Oil injected engines are very lean on oil at idle. The amount of oil is fine for running, not so much for extended sitting. Florida is about as bad as it gets for humidity and internal rust. I've had a couple of them let go after 5 or 10 hours of running; usually the connecting rod bearings. Thats not a fuel injected engine? Most were, in that application but I really didn't pay alot of attention. If it is carburated, tear them down and rebuild them before starting it. The last thing you need is a couple of plugged fuel nozzles from varnish and the engine trying to run on 4 or 5 cylinders while the others are plugged and getting NO OIL or fuel to that cylinder; thats a death wish for the powerhead bearing surfaces. Short of tearing down the powerhead before you start it; I think you're doing everything I would do to try to save it.  Just don't be surprised if it eats a bearing in 5 or 10 hours. On a positive note, I've also seen them sit for 10 years, clean them up, fire it up and never miss a beat so you really never know.

[wingtime]

JJ The merc oil system is driven via a plastic gear on the crank similar to a speedometer drive on a transmission.  It drives a 2"-3" long gear/shaft that drives the oil pump.  I have heard of the shaft rusting or sticking after sitting and causing the plastic drive gear to strip.  

Fitz,  The boat was last registered in 07.  So it has been sitting for at least four or five years.  The owners son tried cleaning the boat up a year or so ago.  I don't know if he tried running it or not but the battery appears to be newer than that.  I cleaned out some roach poop or what ever it was from the flywheel/stator today..  I turned the flywheel by hand just a bit in each direction and it feels VERY smooth with the beginning of some compression.  The sad part is the boat has ONLY 56 hours on the tach...  The original owner was actually killed.    Oh and it is a carburated motor.  I had thought about the carbs..  I should at least blast them out to make sure I don't have a lean cylinder.

[fitz73222]

JJ The merc oil system is driven via a plastic gear on the crank similar to a speedometer drive on a transmission.  It drives a 2"-3" long gear/shaft that drives the oil pump.  I have heard of the shaft rusting or sticking after sitting and causing the plastic drive gear to strip.  

Fitz,  The boat was last registered in 07.  So it has been sitting for at least four or five years.  The owners son tried cleaning the boat up a year or so ago.  I don't know if he tried running it or not but the battery appears to be newer than that.  I cleaned out some roach poop or what ever it was from the flywheel/stator today..  I turned the flywheel by hand just a bit in each direction and it feels VERY smooth with the beginning of some compression.  The sad part is the boat has ONLY 56 hours on the tach...  The original owner was actually killed.    Oh and it is a carburated motor.  I had thought about the carbs..  I should at least blast them out to make sure I don't have a lean cylinder.

You really need to take them off and apart. Soak them in Chem dip carb cleaner from the auto parts store. I'd bet good money the main fuel nozzles and main jets are varnished and plugged. Spray carb cleaner will do nothing for internal varnish. They're really easy carbs to rebuild and I'd be glad to help walk you through it if you haven't done it before. You don't have to get the full blown carb kits, just the gasket kits and 3 carb to intake gaskets. I know its a PITA but you could save the powerhead.  Take off the attenuater cover and get your nose down there and smell. If its got the sickening sweet and sour smell; thats your answer.

[wingtime]

I know that sweet smell well enough.  I already sniffed the fuel tank to see what that smelled like...  It actually smelled like gasoline.  I think the big saving grace is the fact that I believe it has been sitting long enough that the fuel in the tank is non-ethanol.  Either way the fuel system has to be cleaned too.  

I'm not to worried about taking the carbs off and cleaning them.  They seem to be simple enough carbs.  I've cleaned a few carbs now and then.  I'm just not the best at adjusting them.  I'm gonna pull the attenuator tomorrow and sniff around anyways.  So I'll get a look at them.

[wingtime]

Well the carbs are gonna have to come off not matter what!  I pulled off the attenuator and found just what I expected.  I nice little rats nest in the bottom and in the throat of the bottom carb.  At least the butterfly was closed and it kept them out of the intake.

[wingtime]

Nasty carbs!  Thanks for the advice Fitz  I'm glad I didn't try to start it as is..  the bottom carb was full of debris.  Here is a pic of the carbs before I pulled them off today.  I bought a gallon of carb parts cleaner and I have the gasket kits on order.  now the fun starts.  I found a great video on how to rebuild them on you tube.  Looks about what I expected.

[wingtime]

I managed to rebuild my first Mercury carb.  one down and two more to go.  No big deal and like anything else worth the satisfaction and learning experience to do it myself.  Fitz thanks for the push in the right direction.  The insides of the carbs were actually very clean with no varnish or even a sign of old gas.  But the outsides were nasty and there is a good chance some of that gunk had some of the passages blocked up.

[fitz73222]

Screw in the low speed jet screws, counting exactly the amount turns it took to LIGHTLY seat them against the casting. Write it down per each carburator. Then unscrew them out. Usually Mercs are 1 1/4- 1 1/2 turns out from seating the needles. Let the carbs soak about an hour in solution including the low speed needles and float valves. Look at the hollow floats and make sure they are not gas logged by swishing them around. Do one carb at at a time. Wash then out with a garden hose including all the little passages and them compressed air blow dry. WATCH YOUR EYES WHEN BLOWING THE CARBS OUT, THAT STUFF IS ACID. Reassemble using new gaskets. Reset the low speed needles to what you wrote down. When you have them reinstalled we'll walk through developing the Merc ear to get the low speed balance. Don't forget to order the carb to intake gaskets if not included in your gasket kit. Did you get CHEM DIP carb cleaner at the auto parts store?

[wingtime]

Yup I bought a can of carb chem dip at the parts store.  Working on one carb at a time and I did count the number of turns to seat the low speed jet screws...  and your right they have been 1-1/4 to 1-1/2 turns in.  The float bowl areas are very clean and the floats and such look BRAND new.  I have taken them completely apart including the main jets, seat, etc.  Soaking all the metal parts in the chem dip and then rinsing them off and then blowing out all the passages with my air gun. l I have two of them done so far and I'm getting ready to take apart the last one.  I'll take a pic of the insides for ya.   Yes I do need to develop the "Merc" ear since I now own two of them.  Thanks!



OH btw I found this video on youtube.  Not a bad job http://www.youtube.com/watch?v=sjr27WOvvPU

[wingtime]

The bottom bowl was the dirtiest of all three carbs.  I guess all the fuel settled in the lowest bowl.  Here's a pics of the bowl before and after cleaning and all three carbs ready to go back on the motor.  Now I just hope it runs!

[fitz73222]

I like your notes written down on the surgery towel; I do the same thing. Nice clean carbs, your whole shop smells like Chem Dip, light up a cigar...O what a feeling! Boy woundn't be cool to put that 56 hour powerhead on your mid section on the AS. I bet the powerhead swap would be easy. Being a jet, that powerhead is probably cranking 200-205 at the crank and rated 175 at the impeller. I'm sure she will light up now, once you get her back together. You're going to have to do the final idle adjustments in the water at the ramp, tied to the dock, in gear. I assume there is some way to hook up a hose to her in the yard just get it up and running and stabilized before the trip to the ramp. Nice job!

[wingtime]

Carbs are back on, new fuel lines, filter etc.  Cleaned out a rats nest out of the pump housing.  Hooked up water hose....   cranked over like a champ..... no go....   turns out there is no spark. :(   .  Checked the compression.... 130 PS I.  Checking for rat chewed wires, connections etc.  No luck.    Fitz the jet pump is always in gear.  No neutral no shifting.  Just a nozzel for reverse.  The power head on my 200XF is a fresh factory new.

Time for testing I guess.

[fitz73222]

MOB lanyard at helm? Check if its been tripped...