Bad Mechanic - Volvo MD2010

[Ex-Calif]

This should probably be in the confessional. It's a tale of bad mechanics and not paying attention.

The engine on my boat is a 10hp Volvo MD2101 2 cylinder. When I bought the boat she started after a couple of revolutions of the crankshaft and never gave a lick of trouble. Over time and neglect things change and I ignored a lot of symptoms for a long time. We've probably put 300 hours of motoring on it in the last 5 years.

The Symptoms
- It was taking longer to start on first start of the day
- After a 3 week lay off it needed to be bled or it wouldn't start
- She started producing black smoke, especially at start up - lately the black smoke contains heavy black soot (gunk) that pukes out he back until she is warm
- Throttle response is very slow
- Temperatures rose, especially under heavier loads - i.e. fouled prop and towing another boat
- We started to lose fresh coolant over time

My maintenance was basically change oil every 6 months. Change the fuel filter once a year.

Well I came back from a 4 week layoff and none of my old tricks would work. She decided that it was time to take care of her and do some maintenance.

So I am a little PO'd that she won't keep trudging along but I am more pissed at myself for not having taken care of the signs earlier or properly.

Troubleshooting -
- The need to bleed means air is getting in the fuel system - suspect flexible fuel lines
- The black smoke could be injectors and/or a fouled exhaust mixer
- The hard starting could be fuel delivery, injectors, valve adjustment or fouled mixer
- The losing of coolant over time is probably related to the ancient heat exchanger cap
- The temperature could also be related to the heat exchanger being fouled.
- The temperature could also be related to the thermostat
- Pulled the injectors - some dry carbon but not really noticeable fouling.
- Compression is fine

I like to fix things in a system as they go down. Then when I have fixed everything in a system I know when it was fixed and I can eliminate the system from future troubleshooting.

The Plan
- Drain the fuel tank, pull it and clean it
- Exchange injectors (~$280 new and ~$160 exchange each - ouch)
- Replace all rubber fuel lines on the fuel system - eliminate air leak potential
- Replace all crush washers in the fuel delivery system high pressure side
- Pull exhaust mixer and inspect/clean/repair or replace (~$400 - ouch)
- Pull the inlet housing and inspect /clean/repair as necessary
- Adjust valves
- Remove heat exchanger and clean the core
- Replace thermostat and heat exchanger pressure cap
- Change oil and filters
- Change fuel filter
- Change raw impeller
- Clean up raw inlet system for blockages and barnacles.

Parts need to be ordered and they will likely be at least 2 weeks getting here. In the meantime I have a few jobs to do but unfortunately no sailing.

I will post any updates as I work the list.

Any other ideas are welcome.

[senormechanico]

My order of things would be:

1. Clean the exhaust elbow. This could be temp problem as well.
It could also possibly cause enough overheating to burp out coolant.

2. Find fuel air leak.

3. Go sailing.

[Ex-Calif]

Thanks Steve,

My only thought is the black smoke indicating an ever richening mixture could indicate indicates injectors as well as the exhaust mixer.

I suspect but cannot confirm that the engine was overhauled about 7 years ago and about nothing has been done since.

It's a bit of a shotgun approach and costly at about ~$350 for two exchange injectors but peace of mind is good at that price.

Everything else is deferred/delayed preventive maintenance.

I was concerned about maybe having a leak in the diaphragm of the lift pump but it pumps a solid stream so I am going to keep that one in backup.

[b-rad]

if you dont mind me asking where did youfind rebuilt injectors for a volvo for that cheap, I need one for a md7a and most places are quoteing me 450+.
As for your black smoke, a badly foulded prop alone could casue that.

As for your temperature, try to verify it with a infared temp gun, I just spent alot of time and money rebuiding my volvo chasing a running hot problem that turned out to be high resitance in the engine casting between the ground point and the temp sensor. After new water pump, new hoses, newmixing elbow, new echaust hose and pulling the head and cleaning all the cooling passages in the head and the block it still ran hot. Then I replaced the old volvo green-> red guage with a autometer numbered guage and found that with a cold motor it read 115, running a ground to the sensor base brought it down to 85.

[Ex-Calif]

Thanks b-rad. The problem has been progressing over a fair amount of time. Prop's been cleaned several times, even gone through a haulout and bottom painting.

I use marinepartsexpress.com

Browse the parts schematics and search for your engine. I don't know your part number but they offer this number 3803230 for your engine - exchange - for $334.

I have no affiliation - just a satisfied customer - I do like browsing the parts catalogs myself and a quick tip is once you locate your part, copy the PN into the search box at the top of the screen to get an instant pricing, add to cart etc.

[senormechanico]

My MD2020 exhaust elbow gave me no indication that it was getting plugged up until one day I had almost NO POWER! It went from no noticeable symptoms to being very gutless almost instantly. All of a sudden I could only get 1800 rpm or so in neutral.

Until this, I had always prided myself with at least decent maintenance.

Oops!

[Ex-Calif]

I am pulling the mixer tomorrow. I'll let you know what I find...

[DeepFrz]

Singapore should have some good truck repair places. You might be able to get injectors through them for 1/2 the price.

[Ex-Calif]

Well - I half expected to find a lot more stuff once I started digging. The hard part was making the decision to stop sailing and fix things right.

Mixer - Pulled the mixer and while not a lot of carbon the mixer is shot. It is basically two stainless end caps with an exhaust quality rubber tube between. The water is dropped in (mixed) in the exhaust manifold on the engine so the unit is pretty simple. However the flanges on my end caps are paper thin and holed at the 6 o'clock position. There is evidence of water leakage so it's time for a new one.

Fresh Water - There is a rubber hose running outside the engine on the port side. It is dry and cracked when I squeeze it. Time to replace all the hoses and be prepared to change the water fittings based on expected corrosion.

Battery Cables - When I installed new positive cables 2 years ago I bought the bits to change the negative harnesses but didn't execute. With the bilge open it's time.

Saildrive Boot - This one is scary and a safety item. The rubber boot is still flexible and dry but the stainless rings that secure the boots are corroded and looking pretty bad. Time to haul out and change the boots.

Heat Exchanger - I pulled the heat exchanger core and the good news it is in great shape. Volvo made this easy. The tube pack is removable.

Bilge - So if I go that far it's time to pull the plywood floor around the saildrive where the batteries mount. Clean up the bilge, reseal & paint. Clean up the plywood floor or replace it. Clean up all the electricals passing this area and do it right.

Like I said the hard part is deciding you are going to stop sailing until it's fixed.

The worklist is now something like this

- New exhaust mixer and connecting hoses.
- Exchange injectors and all new crush washers and rubber hoses in fuel system
- Remove and clean fuel tank
- Replace all rubber hoses in cooling system - fresh and raw
- Pull engine & saildrive replace saildrive boot. Replace engine mounts
- Clean engine and bilge. Reseal and repaint
- Replace battery primary cables - Clean up other wiring
- Adjust valves, change oil and fuel filters
- Install new bilge pump
- Evaluate doing bottom paint early while hauled out

[senormechanico]

Did that used to be the muffler?

[sabray]

I think its a vat from a sunken galley circa 1600's

[DeepFrz]

Would you get some before and after pictures of the inside of the fuel tank please. Also pictures of some of the gunk you pull out of it. Thanks

[Ex-Calif]

Those are some poor quality photos. I forgot to bring my camera to the boat so they were shot with my Blackberry.

I plan to document all the gory details as I proceed. The bilge and engine are pretty ugly right now but I am motivated to make it right...

My only fear is that when I am done, it won't be anywhere near as cool as the work Del does so I anticipate some embarrassment...

[Stillraining]

Well .....between the likes of craftsmen like Del, James and Bob Kingsland...I gave up competing those types a long time ago XC...but I can out drink all three of them and my taste in beer is definitely better then Bob's...


So post away unfettered XC...I do

[senormechanico]

Don't feel bad, you have a better avatar than Del...

Originally Posted by Stillraining

Well .....between the likes of craftsmen like Del, James and Bob Kingsland...I gave up competing those types a long time ago XC...but I can out drink all three of them and my taste in beer is definitely better then Bob's...


So post away unfettered XC...I do