I'm having my 4BY2-150 Yanmar 250 hr service done on Monday. Besides the manual's checklist of items to be serviced are there other things (based on your experience) I should have the technician inspect etc ? Thanks.
250 hr 4BY2-150 service
- Thread starter baz
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Great post, thanks for doing this Barry.
ttlmac
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Thank you for the great information. Since the impeller was in good shape, did they leave it in or replace it? If they left it, when do they recommend checking or replacing it?
Thanks
Tom
Indian Summer
Thanks
Tom
Indian Summer
I had the 250 hr service performed today by Gallery Marine Service, Seattle. The work performed was excellent. I learned a few things along the way and the process took close to 4 hours with maybe 30 mins used for Q&A. 😀
Engine zincs:
There are two. An upper and lower one. The lower one is always submerged in salt water whereas the top one is left high and dry when engine not running. Subsequently it's typical for the lower zinc to be far more eroded than the upper zinc.
When removing an engine zinc for inspection/replacement there are two things to look for...
1) Obviously the amount of erosion - but more importantly even if the zinc looks hardly eroded you MUST squeeze the zinc between your fingers... and this may surprise you because you will/might find the zinc will completely collapse under slight squeezing pressure... it's essentially hollow and just a shell and has been eaten away from the inside.
2) Because the top zinc goes through wet and dry states a white scale can build up on the zinc's surface over time. If this white scale completely covers the outer surface of the zinc it makes the zinc useless. I suppose the scale can be removed but for me I would simply replace the zinc and be done with it. Typically, when the scale is removed the zinc's color is dark charcoal in color rather than the nice light gray color when brand new. See picture below.
3) The engine zincs can be a PITA to unscrew. There's not much room to the side of the engine to get a full length wrench engaged. See picture below where the 15/16" wrench has been cut in the middle to make life easier. This was a tip I picked up at the 2011 Bremerton meeting... and BTW my Yanmar technician was very pleased to use them today. 🙂
4) New copper washers
New ones should be used. I had bought two engine zincs from Ranger Tugs part dept and don't recall having the washers sent to me as part of the engine zinc order I placed. Be sure to get new copper washers.
Primary fuel filter:
When replacing the primary fuel filter it's not sufficient to just hand tighten (as you normally would do) screwing in. This is because there's an inner seal that has to be dealt with and hand tightening will seal this one but not the main one. Thus a filter wrench needs to be used to tighten it up sufficiently to make a good seal at the top. The primary fuel filter is the pressure side and the pressure can push the filter off if not tightened down correctly.
Batteries:
I've checked the fluid level in my 4 batteries over past 3 and a bit years and the level has always been at the proper level. Today they were checked again and the level was where it should be. This amazes me and it must be that the factory installed battery charger is doing a fine job of not overcharging and if the engine isn't running the boat is connected to shore power. So over the last three years the batteries have either been charging via the onboard battery charger when docked and connected to shore power or being kept charged with the engine running. I'm hoping I can get another 3 years at least from these factory installed batteries.
The technician recommend I replace the batteries when the time comes with AGM (Absorbed Glass Matt) style batteries. What do others think ?
Cost of AGM batteries over lead acid batteries is a factor of 1.5, so I'm told.
Water Impeller:
This was examined and no issues with hairline cracks and no vanes were missing. 🙂 The technician said if a vane were to be missing and not located in the impeller cavity every effort should be taken to find the missing vane or the pieces otherwise it/they could clog the water passages and cause restricted flow and subsequent engine over heating. Access to the impeller housing is kind of awkward but not impossible. First the impeller drive belt needs to be removed. The belt comes off the crank shaft pulley and only drives the impeller. A screwdriver can be placed under the belt and the crank turned to ease the belt off. Then the impeller belt pulley needs to be aligned so that 4 hex bolts can be removed and the housing will then be exposed. To access this part of the engine the vertical wood of the cabin step needs to be removed -- 4 screws hold it in place.
Engine
This has been discussed here before. It's good practice to run this 4BY2-150 engine at around 3800 RPM for about 5 to 10 mins when out on the boat. This clears out built up carbon deposits and keeps the engine 'clean'. If this is not done eventually the engine exhaust will start smoking -- and no one likes this -- especially if the boat is up for sale. 🙂
Tip for always ensuring the engines sea cock is open before starting the engine
Attach and easy to remove engine ignition key to the sea cock's valve lever. Thus to start the engine one must open the engine hatch to gain access to the ignition key and be reminded to open the valve. 😎
Engine zincs:
There are two. An upper and lower one. The lower one is always submerged in salt water whereas the top one is left high and dry when engine not running. Subsequently it's typical for the lower zinc to be far more eroded than the upper zinc.
When removing an engine zinc for inspection/replacement there are two things to look for...
1) Obviously the amount of erosion - but more importantly even if the zinc looks hardly eroded you MUST squeeze the zinc between your fingers... and this may surprise you because you will/might find the zinc will completely collapse under slight squeezing pressure... it's essentially hollow and just a shell and has been eaten away from the inside.
2) Because the top zinc goes through wet and dry states a white scale can build up on the zinc's surface over time. If this white scale completely covers the outer surface of the zinc it makes the zinc useless. I suppose the scale can be removed but for me I would simply replace the zinc and be done with it. Typically, when the scale is removed the zinc's color is dark charcoal in color rather than the nice light gray color when brand new. See picture below.
3) The engine zincs can be a PITA to unscrew. There's not much room to the side of the engine to get a full length wrench engaged. See picture below where the 15/16" wrench has been cut in the middle to make life easier. This was a tip I picked up at the 2011 Bremerton meeting... and BTW my Yanmar technician was very pleased to use them today. 🙂
4) New copper washers
New ones should be used. I had bought two engine zincs from Ranger Tugs part dept and don't recall having the washers sent to me as part of the engine zinc order I placed. Be sure to get new copper washers.
Primary fuel filter:
When replacing the primary fuel filter it's not sufficient to just hand tighten (as you normally would do) screwing in. This is because there's an inner seal that has to be dealt with and hand tightening will seal this one but not the main one. Thus a filter wrench needs to be used to tighten it up sufficiently to make a good seal at the top. The primary fuel filter is the pressure side and the pressure can push the filter off if not tightened down correctly.
Batteries:
I've checked the fluid level in my 4 batteries over past 3 and a bit years and the level has always been at the proper level. Today they were checked again and the level was where it should be. This amazes me and it must be that the factory installed battery charger is doing a fine job of not overcharging and if the engine isn't running the boat is connected to shore power. So over the last three years the batteries have either been charging via the onboard battery charger when docked and connected to shore power or being kept charged with the engine running. I'm hoping I can get another 3 years at least from these factory installed batteries.
The technician recommend I replace the batteries when the time comes with AGM (Absorbed Glass Matt) style batteries. What do others think ?
Cost of AGM batteries over lead acid batteries is a factor of 1.5, so I'm told.
Water Impeller:
This was examined and no issues with hairline cracks and no vanes were missing. 🙂 The technician said if a vane were to be missing and not located in the impeller cavity every effort should be taken to find the missing vane or the pieces otherwise it/they could clog the water passages and cause restricted flow and subsequent engine over heating. Access to the impeller housing is kind of awkward but not impossible. First the impeller drive belt needs to be removed. The belt comes off the crank shaft pulley and only drives the impeller. A screwdriver can be placed under the belt and the crank turned to ease the belt off. Then the impeller belt pulley needs to be aligned so that 4 hex bolts can be removed and the housing will then be exposed. To access this part of the engine the vertical wood of the cabin step needs to be removed -- 4 screws hold it in place.
Engine
This has been discussed here before. It's good practice to run this 4BY2-150 engine at around 3800 RPM for about 5 to 10 mins when out on the boat. This clears out built up carbon deposits and keeps the engine 'clean'. If this is not done eventually the engine exhaust will start smoking -- and no one likes this -- especially if the boat is up for sale. 🙂
Tip for always ensuring the engines sea cock is open before starting the engine
Attach and easy to remove engine ignition key to the sea cock's valve lever. Thus to start the engine one must open the engine hatch to gain access to the ignition key and be reminded to open the valve. 😎
ttlmac":2hf06gbr said:
The technician saw no reason to replace it, so it was left as is. Technician did say that a spare impeller is a must for being on board. If impeller does fail while on the water and engine starts to over heat it's better to take time/effort replacing the impeller rather than alternatives such as towing if indeed that's available option.
Technician advised that the impeller be examined at engine's 500 hr service. So long as water is being pushed out of the exhaust then the impeller is functioning -- and of course engine temp should be normal. If engine temp is seen above normal range then one should suspect something and the first thing to be checked would be the impeller -- maybe a vane has been shed reducing the impeller's effectiveness for pushing sufficient sea water for cooling the engine. The impeller is constructed of a tough rubber/plastic compound, and even so, the wear and tear on it will take its toll over time and will eventually start failing. Proper periodic maintenance of the engine along with periodic examination for hairline cracks in the impeller will go a long way to ensure impeller failure does not occur when least expected.
I did question the technician about leaving the current impeller in place (especially since he went to the trouble and effort of accessing it) -- but he insisted that it was sensible to leave as is and had complete confidence in his decision. Mind you, he also gave anecdotal evidence where all the impeller vanes had been shed in an engine he once serviced yet amazingly enough the exhaust still showed evidence of water being pushed out. Maybe some portion of the vane's root material remained and was sufficient to push some water through the engine's heat exchanger.
The strongest advice given by the technician was for keeping to the Yanmar engine service schedule. He's seen too many neglected engines and very sad boat owners as a consequence. IMO the cost of engine maintenance be it DIY and/or professional service technicians is chicken feed compared to the alternative cost of repairs due to neglect over time.
