YANMAR 440 MAINTENANCE ??


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37pc

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After 30 years, this is my first diesel boat. I have heard to just keep the fuel and oil clean and they will run forever. Question.... I have Racor fuel filterers . They vary from 2 to 30 microns. I am not sure which to use. Also is this something easy to do? Does air get trapped? Is there a secondary fuel filter?
I have always worked on my own engines but this is all new to me.. Any advise would be appreciated. Thanks
 
I'm not sure of the which micron filter you need, I can check while I'm on my boat tomorrow. They are very easy to change, just shut the fuel off and unscrew the top and pull them out by the small plastic handles that are built into the filter. Put the new filters in SLOWLY so they can absorb the fuel then top off the canister with diesel from a can. You want to make sure you have a bucket or something to put the old filters in when you take them out, they will make a mess.

There is another filter on the engine. These are Yanmar filters and a pain to change but they don't need to be done very often.

You are correct, fuel and oil is very important but the proper loading is key. Make sure you can hit 3400 rpm wide open fully loaded, if not you are overloaded and they may pay the ultimate price.

I've had my Yanmars for 2 seasons and they have been great. I've done a ton of maintenance myself so feel free to ask.
 
Thanks.. When you say loaded , do you mean overweight? I believe the motors run between 3300 & 3400. I will have to double check that.
How do you know when the secondary filters need changing? I have read if the primary filters are too thick it will too much vacuum and starve the motors.
I suppose changing the oil is straight forward. I see two filters facing each other. Are there anymore? I also see at least one zinc to replace.... Thanks for your help!
 
Racor's have different color writing on the top of them to differentiate micron sizes. I use red writing. Not sure I think it is a 20 Micron. Like Nate said changing the Racor is pretty simple. Changing the secondary filter on the engine can be pretty messy. Unfortunately when you drain the secondary the drain plug is not on the very bottom of the cover. When you open the bolt on the very bottom which holds it in place a couple ounces of diesel fuel will pour out. A cut down bottom of a 2 liter soda bottle can come in handy for this messy chore.
 
uite often

Assuming that your transmission cooler does not have a zinc there are 5 zincs on each motor. They do need to be checked and changed quite often especially in salt water. Changing the oil filters can be messy, because they are rather large and hold alot of oil. I always punch a hole in the top of them and give them a chance to drain into the engine. Under the 2 filters there is a little well I stuff with oil absorbers.
 
You want to be able to hit 3400 rpm with the boat full of all your stuff, a good amount of fuel and water. If you can get there you are safe. Also, you should only run about 80% of wide open throttle for extended periods of time.
 
The fuel filters on your engine are 2 micron, I would recommend 10 micron for the Racor's. Be sure to use larger micron filters in the Racor filters than those mounted on the engine.
 
I just verified it. When I purchased my boat the factory installed a 10 Micron in the racor. I took Mack Boring class on Yanmar motors and was told to change it to a 30 micron. Gurryman is correct the secondary filter is 2 micron.
 
Wow! Great tips guys. I am confident I can take care of these myself. Does the bowl on the bottom of the filter need to be drained? Does anyone know how often the secondary fuel filter needs replacing? What happens of you cannot get to 3400 rpm? I am pretty sure I got 3300 with full fuel & water tanks... Is 2500 RPMs the 'sweet spot'? I just took a trip and ran between 2700 & 2800 and burned 25 GHP doing about 23 knots. UGH!
 
I think you will find 2500 rpm is the most economical. For the bowl, you can drain it but to me it seems like the fuel never stops coming even though it is shut off.

You will need to prime after this filter is changed, the instructions are in the manual and it's pretty easy to do, there is a small pump right next to the bowl.

Make sure you have the manuals, they will tell you how ofter things need to be changed. The manuals are available online. The good part about diesels is they are made for a lot of hours so most items don't need to be done very frequently. I have 550 hours on mine and the impellers look brand new, you don't need to replace for a 1000 hours.

I was nervous about diesels but I would never want to go back now.
 
Thanks. I have the manual that came with the boat, Anothe issue is , how do you keep the transom door closed?
 
"2500 rpm is the most economical",
Figures from boattest.com
 

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How are you measuring speed?
Speed needs to measured by GPS, Raymarine Tri-Data is not that accurate.
cheers
 
Thanks.. I guess how the boat is loaded makes a difference. I have a set of spare props onboard and had a full tank of water. I should take the props off the boat expect when making far away trips.
 
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