Yanmar 4BY2 180 HP won’t start

Soooooooooooo, finally got the new starter for a paltry $600 after a marine dealer wanted $1200 for one with a Yanmar name on the box. Lets just say it involved my brother-in-law, a seedy neighborhood, a driveway overgrown with weeds, a tiny handmade wooden vestibule to a decaying brick building and a sliding panel through which we exchanged my credit card for a brand new starter. No kidding. The guy was extremely nice and mentioned that these starters are "captive" by Yanmar, but he was able to get one in a plain box at a much lower price. It is identical to the old one and fit perfectly.

Story not over yet.

After re-assembling the engine, the moment of truth produced the exact same result! No go on the engine even the Parallel switch ON. After some serious head-scratching, he removed the ground from the transmission and fastened it directly to one of the starter bolts about 6 inches away. Said that's gotta work and that these engines should have a second grounding wire like he sees on other marine motors. Still no go. After checking each battery voltage at the batteries (all good) he said its gotta be a bad ground or positive somewhere in the starting circuit. After hunting with a voltage / amp tester with everything looking fine, we tried jumper cables off the start battery... still no go.

When all else fails... RTFM.

Given the symptoms the starter was having, the trouble shooting diagram resulting in a fix labeled "Check Engine Condition". Uh huh.

Soooooooooo... he finally started poking around at the forward end of the engine. Mmmmmm, the alternator belt and pulley didn't move when I tried starting the motor. He eased the tensioner, took the belt off the pulley and tucked it out of the way of any moving parts and the engine fired up instantly.

He removed the starter and the 150 amp Valeo alternator was frozen solid. The pulley wheel was immovable and the body was corroded as evidenced by all the paint being bumpy (but oddly still intact). Luckily, that gave me my first good look at the port forward motor mount from the access step in the cabin and it turns out the fastening nut had backed out a good quarter of an inch, so some good has come from all this in terms of preventing a future disaster. He looked at the other mounts which were all still secure.

Related/unrelated aside? The alternator is on the same side (port) as the generator which suffered a corroded starter after I took delivery of the boat last September. The foam seal on the seat directly above the generator had failed and saltwater wash over the gunnel must have made its way down to the generator starter which is in accessible unless you remove the entire generator. I had it removed and refurbished the whole thing, but I'm guessing salt water in the bilge must have gotten to the engine alternator as well.

Does anyone give their engine compartment a gentle freshwater rinse? Will that only create more problems?

GF waiting for another part...
 
Bummer! Are your gutter grills removed? Are you theoretical seals on the compartment lids okay? I replaced my engine lid seals with a more robust and narrower seal. And yes, I would lightly spray below and wipe things up daily after every voyage.
 
It is unfortunate that the step of checking free rotation of the engine in troubleshooting was missed. Never over look a Hydrolock although it seemed to be a long shot. I must say I have never had an alternator locked up cause an engine not to turn over. I have had alternators lock up and make a lot of belt noise. I have never had an alternator function well making no noise and then be locked up.

Salt water is very destructive to metal and electrical components. When working as a service technician east coast area. I kept a spray bottle of CRC strapped to my tool box. After servicing an engine I would give the entire engine a light spray mist of CRC penetrating oil. Just enough to see a sheen on the components of the engine ,block, manifolds, and electrical components. I also did this when winterizing the engine. The last thing to do was give the engine a light coating of CRC. I did that to my D3 from day one when it was new. If you looked at it today you would think it just came out of the shipping container and was just installed.

Keeping the compartment dry and salt free will eliminate a lot of issues. Good job on the troubleshooting who would have ever figured it was a locked up alternator stopping a diesel from starting!!!
 
Unfortunately I did not go into depth with my first comment on this thread. I suggested a hydraulic lock and never suggested to check by turning the engine manually. That may have led to the real issue. My mistake!
 
Epilogue: new alternator installed, engine fired up nicely, good charge going to the batteries during run. The mechanic did make an interesting suggestions during the sea trial. He noticed the engine running consistently at a temp of 199-202F at 3700 RPMs. He said he'd like to see it a bit lower. I happened to have a replacement thermostat that came with the boat which was rated at 88C (190F). His comment was that was probably the spec for this engine when used in cars to meet emissions requirements (not a bad thing) and suggested getting a thermostat that would run a little cooler closer to 175F (79C). Thoughts? GF
 
The rated temperature of a thermostat is the point the thermostat opens. Example: A 175F thermostat will begin to open at 173 F to 177F and the thermostat will be fully open about 20 degrees above that temperature. Even with that explanation I would install what Yanmar recommends . I know the D3 has a thermostat that begins to open at 176F but operates at the higher temperatures at higher rpm ranges WOT around 193F to 200F. I am working on a Yanmar 4LHA-STP 240 hp direct injection that Yanmar specifies a 71C thermostat 160F which would be full open at 180F. I would not compare this Yanmar to the 4BY2 that is full electronic.

The biggest issue with the higher temperature operation of the engines D3 and 4BY2 in R25,R27 and C26 is the through hull piping is incorrectly sized (1"). Both engines have 1 1/4" inlet and outlets on the raw water pumps. These pumps were sized by the engine manufacture to supply enough water for adequate cooling. 1" piping provides marginal cooling to a perfect cooling system. If there are any restrictions to the system an increase in temperature will be experienced. If operating a engine in salt water environments for a few years deposits build up in the cooling system, along with midseason warmer sea water, any obstructions in the cooling systems,the marginal pipe sizing will prove to be an issue. I believe the temperatures you were experiencing are about average to any R27 or R25 that is powered with the 4BY2 at high cruise speed. If 3700 rpm is you WOT then that to is a bit low and increasing exhaust temperature. The exhaust manifold is part of the closed cool loop. This could also add to the higher temperature operation that you experienced.
 
Good read while I'm sitting here looking at my 4by2 in my R27. I like doing my own mechanicing. 😀
Haven't had any major issues at 620 hrs. Knock on wood. It does use a bit of oil. I had an analysis done about 50 hrs ago and no unreasonable findings.
 
Thanks for the insights Brian. 3700 RPM is where this power boat newbie is comfortable at as I get to know the boat. What is considered WOT for the 4BY2 and how long can one run at that rate? Thanks all. GF
 
GaylesFaerie":27lpvxvu said:
Epilogue: new alternator installed, engine fired up nicely, good charge going to the batteries during run. The mechanic did make an interesting suggestions during the sea trial. He noticed the engine running consistently at a temp of 199-202F at 3700 RPMs. He said he'd like to see it a bit lower. I happened to have a replacement thermostat that came with the boat which was rated at 88C (190F). His comment was that was probably the spec for this engine when used in cars to meet emissions requirements (not a bad thing) and suggested getting a thermostat that would run a little cooler closer to 175F (79C). Thoughts? GF

The thermostat should be 85 C which is 185F The thermostat would not be the first thing I would suspect. Besides, it is not where the detailed manual may show. It is in the elbow below the heat exchanger. One of the most time consuming jobs to undertake. I actually had the thermostat dislodge and was running too cool.
When was the last time you flushed your heat exchanger with Rid-lyme or Barnacle Buster? Check your intake and make sure you are getting good flow. Under normal cruise (2,6r0 RPM) I was getting around 196 degrees at WOT it would go as high as 206. Keep in mind that ambient water temperature makes a difference.
 
We had an issue at our 4BY2-150 at the 600 hour service several years ago where the Yanmar certified mechanic in Anacortes took out 3 gallons of coolant for a flush and put back in 2 gallons of coolant. We ran several hours at low RPM to Ganges without issue. The next day we discovered that anything over 2,500 rpm caused the engine to run hotter than normal. So we limped back to Anacortes to figure out what went wrong.

During that debacle, I was told by several experienced Yanmar mechanics and company folks in the US and Canada that you can run the 4BY2 engine safely up to 210 degrees for short periods and it’s ok to run up to 205 degrees for extended periods.

Our Yanmar 4by2-150 now runs all day at 3,000 rpm showing 196 to 198 degrees in the cool PNW waters.
 
GaylesFaerie":2ojkic4k said:
.......Luckily, that gave me my first good look at the port forward motor mount from the access step in the cabin and it turns out the fastening nut had backed out a good quarter of an inch, so some good has come from all this in terms of preventing a future disaster. He looked at the other mounts which were all still secure.

As you know, our boats are nine serial numbers apart. My port forward engine mount lower nut had backed all the way down to the mount. All others were tight and secure, just as were yours. I think the genesis of our engine mount problem was when the boat was built. I’ll bet money there are boats of our vintage with unsecured forward engine mounts.
 
Thanks KnotFlying and scross. So it sounds like my temp is not out of a normal range. The current water temp in Long Island Sound is 72+F and the boat runs at 199 - 202 at 3500 RPM. I've only had the boat a year and not touched the heat exchanger. What procedure do you use to flush with Barnacle Buster? And Caspers that is spooky that the same port forward motor mounts got loose on both boats made so close together. Other TugNuts with similar vintage boats beware! GF
 
This is how I did it. You may want to do this at your next impeller change and kill two birds with one stone.

Materials List

Small wooden plugs
3 Feet 3/4” Hose (or Other Size as required for the Input side of the
Raw Water Washdown Pump)
3 feet 3/4” hose (or other size and reducers as required to connect output side of the raw water washdown pump to the input side of the raw water cooling system)
3 feet of hose to connect to the exit side of the raw water system by
the mixing elbow
Hose Clamps
Two 3 gallon Buckets
1 – 1.5 gallons Rydlyme

Procedure:

Close Raw Water Seacock

Remove Impeller
Replace Impeller Cover without the Impeller 

Remove the engine zincs and replace the caps

Disconnect and plug the water input to the stuffing box. On the 4BY2 disconnect hose from mixing elbow and plug. On the 110 disconnect the hose at the stuffing box and plug both the hose and the nipple on the stuffing box.

Remove Raw Water Washdown outlet and Inlet Hoses
Connect and Clamp 3 foot hose to input side of Raw Water Washdown Pump and connect hose from Outlet Side of Raw Water Washdown to Input side of Cooling System

For a Yanmar 110 HP use a reducer for the 3 foot ¾” output hose and a short length of 1” hose to connect the output from the raw water washdown pump to the input of the transmission oil cooler

For 4BY2 connect the output side of the raw water washdown to the sea strainer. This can be accomplished by just switching the hose from the sea strainer feeding the raw water pump to the output side at the raw water pump.

Remove the heat exchanger outlet water hose from the exhaust mixing elbow water input.
Connect a 3 foot hose from the heat exchanger outlet to a bucket

For the Yanmar 110 use a 3 foot 1” hose.

For the Yanmar 4BY2 use a 1.25” to ¾' reducer and a ¾ threaded to a 3/4” barbed fitting connected to a 3' 3/4” hose

Fill the Bucket with two gallons of fresh water
Use the pump to flush the system twice, replacing the water between flushes.

Fill the bucket with one to 1.5 gallons of Rydlyme (biodegradable)
Circulate the Rydlyme for two hours intermittently using the pump Dispose of the Rydlyme

Flush the system with fresh water and two buckets twice or until water exiting is clear.

Now would be a fine time to inspect and clean your mixing elbow.

Reconnect all the hoses as originally installed.
Replace the impeller.

Replace the engine zincs

Open the seacock.

Start the engine and check for leaks.
 
I also had a starting problem on my 2011 Ranger 27 Classic Yanmar 4BY2-180 and I will do my best to describe want cause it. Last year I wanted to check my engine hours and also reconfigure the Yanmar Engine Display. I turn on the house batteries and turn the key ignition switch to what I though was position one. After about 20 minutes I had completed my task and turn off key ignition switch. I turn off the House battery switch and immediately I smell the fear electrical burn smell. The smell was strongest in the engine compartment which I spent some time looking for anything that looks suspicious. I then turn on both the house battery and engine battery and try to start the engine and nothing happen but I did notice that the Yanmar Display not working either.

I immediately suspect something in the engine starter motor or wiring. I spent two days with mirrors and flashlights trying to see anything around the starter solenoid with not much luck. I pull the boat out and had a friend of mine that is retired boat mechanic look it over and he agreed that the starter solenoid is fried. Getting to the starter motor on Yanmar 4BY2-180 is no easy task so I decided to install a new starter motor and solenoid along with some new wiring. The engine started up just fine after the repair.

I cause the problem by accidently turning the key switch to the start position and not position one.
The starter solenoid was engage for whole time which cause it heat up and fail. If I had turn on both the House and Engine Batteries the starter motor would had turn over the engine, which would have heard.

I’m not sure why the factory wired the Yanmar 4BY2-180 ICU and starting circuit through the House Batteries and not through the Engine Battery. The Engine Battery on my boat only powers the starter motor.

Expensive lesson to learn is turn on both House and Engine Batteries when checking or reconfigure the Yanmar Engine Display.
 
Thanks KnotFlying, love the details to make it easy and understandable.
 
This is how I did it. You may want to do this at your next impeller change and kill two birds with one stone.

Materials List

Small wooden plugs
3 Feet 3/4” Hose (or Other Size as required for the Input side of the
Raw Water Washdown Pump)
3 feet 3/4” hose (or other size and reducers as required to connect output side of the raw water washdown pump to the input side of the raw water cooling system)
3 feet of hose to connect to the exit side of the raw water system by
the mixing elbow
Hose Clamps
Two 3 gallon Buckets
1 – 1.5 gallons Rydlyme

Procedure:

Close Raw Water Seacock

Remove Impeller
Replace Impeller Cover without the Impeller 

Remove the engine zincs and replace the caps

Disconnect and plug the water input to the stuffing box. On the 4BY2 disconnect hose from mixing elbow and plug. On the 110 disconnect the hose at the stuffing box and plug both the hose and the nipple on the stuffing box.

Remove Raw Water Washdown outlet and Inlet Hoses
Connect and Clamp 3 foot hose to input side of Raw Water Washdown Pump and connect hose from Outlet Side of Raw Water Washdown to Input side of Cooling System

For a Yanmar 110 HP use a reducer for the 3 foot ¾” output hose and a short length of 1” hose to connect the output from the raw water washdown pump to the input of the transmission oil cooler

For 4BY2 connect the output side of the raw water washdown to the sea strainer. This can be accomplished by just switching the hose from the sea strainer feeding the raw water pump to the output side at the raw water pump.

Remove the heat exchanger outlet water hose from the exhaust mixing elbow water input.
Connect a 3 foot hose from the heat exchanger outlet to a bucket

For the Yanmar 110 use a 3 foot 1” hose.

For the Yanmar 4BY2 use a 1.25” to ¾' reducer and a ¾ threaded to a 3/4” barbed fitting connected to a 3' 3/4” hose

Fill the Bucket with two gallons of fresh water
Use the pump to flush the system twice, replacing the water between flushes.

Fill the bucket with one to 1.5 gallons of Rydlyme (biodegradable)
Circulate the Rydlyme for two hours intermittently using the pump Dispose of the Rydlyme

Flush the system with fresh water and two buckets twice or until water exiting is clear.

Now would be a fine time to inspect and clean your mixing elbow.

Reconnect all the hoses as originally installed.
Replace the impeller.

Replace the engine zincs

Open the seacock.

Start the engine and check for leaks.
Hey Mike, great informative post on flushing the the 4BY2. I have the 2012 R27 with the Yanmar 180. My question is about disconnecting and plugging the inlet to the mixing box. “On the 4BY2 disconnect hose from mixing elbow and plug”…..do I need to do this since we’re already bypassing the mixing elbow? My boat is on the trailer and not in the water. Thanks in advance
 
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