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  • #41160

    Mick Huestis
    Participant
    Vessel Name: Silly Blue
    Engines: 4LHA-STP
    Location: Brisbane
    Country: Australia

    Hello – keen on some guidance please.

    My 4LHA-STP (240hp) engine is overheating.

    2000 hours.

    Coolers / heat exchanger are all just cleaned and looking great.

    New impellor fitted in sea water pump, water is flowing through the sea water circuit.

    I am not losing any engine coolant on the fresh water side.

    Not sure where to look next.

    any guidance appreciated.

    cheers

Viewing 20 replies - 1 through 20 (of 25 total)
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  • #87599

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    The manual is far from gospel ….. All environments and sea water conditions will play varying levels of havoc.
    So if the manual is taken verbatim the engine that is docked in the salty sea gets the same maintenance protocol as the one slipped in Lake Michigan? No way.

    If the pump has not been serviced in 8 years I gather that neither has the remainder of the seawater circuit. Now is the time. Best is to pull all from the engine and bench service – clean, test, paint, new gaskets/o-rings/etc…

    #87566

    yellowhty326
    Participant

    twin Yanmar 4LHA-STP sea water passage cleaning questions

    Hi, Happy New Year to every one!

    Last year I bought a Mainship 2005 trawler with twin Yanmar 4LHA_STP engines which only recorded 300 hours. I have been driving it for 150 hours since May 2019. The engines run perfectly and temperature range at 75 degrees below 3000 RPM and at 84 degree at 3400 PRM, and also I checked the impellers in good condition and the water flow very normal. One of my experienced marine mechanic reminds me that the engines may need to do a sea water service since the record shows the impeller pump hasn’t been serviced since Feb-2011. But according to the manual, it only needs to check or replace the impeller at 1000 hours or 4 years and clear and check the sea water passage at every 2000 hours. So my question is –do I need to check and clean raw water pump, inter cooler, oil cooler , after cooler and all the sea water passage now? I used to have Yanmar 6LAPA, its manual says the sea water passage needs to be checked 1250 hours or every 5 years. Thus my other question is why 4LHA-STP only need to clear the sea water passage at 2000 hours but the 5 years? The last question is what exactly mean in the manual “to clear and check sea water passage?” Does it mean I have to dissemble all the coolers and heat exchanges to check and clean them ? Thank you very much!

    #42431

    Mick Huestis
    Participant
    Vessel Name: Silly Blue
    Engines: 4LHA-STP
    Location: Brisbane
    Country: Australia

    Running out of things to check.

    Wet exhaust was clear, like the day I built it.
    Dry riser was perfect. No moisture. Working perfectly (thanks to Tony’s Tips 5 years ago).
    Turbo exhaust was silky velvet soot, clearly no moisture leaking through exhaust manifold / header tank.
    Engine oil lab test was good, zero water in crank case.
    Gave coolant pump a spin today, seems to be flowing normally.
    After cooler, totally clear, o rings still greased, all good (thanks to Tony’s Tips 5 years ago) regreased and ready to go again.
    Checked coolant drains – all clear, flowing clear with no gel or sediment. No concern of heat exchanger being gelled up on coolant side.

    Plan forward
    – coolant side alkaline clean
    – new coolant
    – new thermostat
    – New salt water impeller
    – test run and see what is happening

    Next things to check, in order
    – salt water pump to come off for a look see, if that doesn’t find it;
    – coolant pump to be pulled off for a look

    I will find the heating issue!

    Cheers

    #41959

    Bill Fuller
    Participant
    Vessel Name: Audax
    Engines: Yanmar 4LHA-STE
    Location: San Diego, CA
    Country: USA

    Mick

    When you replace the coolant, be sure to use the proper one, this is very important for the survival of the exhaust manifold, which is aluminum. The coolant should be some variation or orange. And will specifically say no phosphates or silicates. Look at the additives in your coolant and see if there are and words that contain silicate or phosphate. As an FYI, I change my coolant every year, just to make sure everything stays perfect all the time. I get laughed at because it looks like new when it comes out each year.

    Also, please remove the raw water pump and check it out and do as I mentioned above. And replace the impeller. I am betting on the impeller being your total problem. As I said, the ones from Yanmar are very erratic in how long they continue to pump effectively. And order some of Tonys impellers.

    Tony, I can’t remember whether 8 or 12. I will check my spares when I am at the boat.

    Bill

    #41958

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    how do we measure the Yanmar sea water pump to determine if the OD and cam is worn too far?

    some water I run in is silty, could be abrasive?

    cheers

    Mick

    So you do run the bottom with your prop? When docking or ?? Where is your seawater pickup in relation to the prop?

    Best way would be to have your pump side by side with a new one and mic and compare but chances are there’s not one on a shelf nearby? Not sure if you’ll find printed dimensional drawings/specs..

    #41955

    Mick Huestis
    Participant
    Vessel Name: Silly Blue
    Engines: 4LHA-STP
    Location: Brisbane
    Country: Australia

    Engine oil lab analysis normal

    I still don’t know what my problem is, but some good news – today received back engine oil laboratory analysis.

    No water in oil – no abnormal results.

    Rules out the head gasket I think.

    progress…

    Got a coat of paint on the aftercooler, ready to go back together with new o-rings and plenty of grease.

    No leak between salt water side and oil side of oil cooler.

    back together and then coolant side flush out, replace thermostat, try again.

    #41949

    Mick Huestis
    Participant
    Vessel Name: Silly Blue
    Engines: 4LHA-STP
    Location: Brisbane
    Country: Australia

    how do we measure the Yanmar sea water pump to determine if the OD and cam is worn too far?

    some water I run in is silty, could be abrasive?

    cheers
    Mick

    #41945

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    Bill,

    Good info……………………….

    Curious — 8 Blade or 12 Blade — what seems to be best?? I have lost track..

    As to the cam–Yes, NO replaceable cam–it’s part of the housing casting, but the inside of the pump can and does wear– both in depth and “average OD”…………….But for sure, that pump is superior to anything Sherwood ever came up with..

    Really sad Yanmar has not resurrected this engine as a CR T3 package–instead, they wasted their $$ on the 6LYA which will never compete with Cummins QSB 5.9, yet alone the 6.7.

    Tony

    #41896

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    No cam plate to cause problems

    Thanks for the great post Bill. As to the cam, I was thinking of the Johnson pump in the 6LP which does have a cam…

    #41860

    Mick Huestis
    Participant
    Vessel Name: Silly Blue
    Engines: 4LHA-STP
    Location: Brisbane
    Country: Australia

    Hi Bill

    The coolant is Fluro green. Now I’ve checked, It says to change every two years. It was recommended based on all different metal types in the system. Doesn’t say anything about silicates or phosphates. Unfortunately have gone 4 years on the coolant, didn’t realise it needed changing yet. Thought it was long life but was wrong.

    Cheers

    #41679

    Bill Fuller
    Participant
    Vessel Name: Audax
    Engines: Yanmar 4LHA-STE
    Location: San Diego, CA
    Country: USA

    Nick,
    I have been running a set of these motors for almost 19 years now with 6,000+ hours. I few thoughts for you and questions.

    1. The coolant you mentioned, I am not familiar with it. Is it an extended life coolant? Does it state specifically that it does not contain silicates or phosphates, this is very important. What color is it?

    2.. As for the raw water pump, they are really a superior unit. No cam plate to cause problems, nice solid bronze construction, bearing and seals seem to last forever. I have yet to rebuild one. I would suggest that you purchase a set of Tonys impellers, they are far superior to the ones Yanmar sells. In fact, I would replace your current impeller and recheck your temperature before going much further. I have personally seen the Yanmar impellers stop pumping properly in a very short time. And when removed look just fine.

    3. Pump removal suggestions. It sounds like you have never removed the raw water pump from the engine. A few tips. Remove he alternator or move t out of the way. Remove the bracket that holds the alternator. These are easy to do and greatly increase access to the nuts and bolts that hold the pump. There are 2 bolts and 2 studs that hold the pump. Check the wear plate below the impeller and turn it upside down. Now you have a clean surface against the impeller. Polish the inside of the cap. If the housing of the pump shows scoring or wear, polish it too, most likely not needed. But do replace the impeller and check again.

    4. Still on the pump, as an example, not too long ago when I was doing my yearly maintenance, which includes an impeller change, Tony was out of impellers and I used Yanmar parts. After about 200 hours, I started to notice more than normal steam out of my port motor. The steam increased on the next trip to where I was concerned. No noticeable engine temp increase. Water flow “looked” fine. Pulled the pump, impeller looked perfect, changed it anyway problem solved! As a side note, I will never “look” at an impeller without changing it.

    5. Buy impellers from Tony. I think you can order online.

    I had more thoughts but now I can’t remember them. Enough for now anyway. If you have any questions I will be glad to share knowledge I have gained over the last 19 years with these motors.

    Bill

    #41524

    Mick Huestis
    Participant
    Vessel Name: Silly Blue
    Engines: 4LHA-STP
    Location: Brisbane
    Country: Australia

    Hi Rob

    Raw water Intake hose is 7 years old, steel wire reinforced industrial pump intake hose,

    Coolant side. Water pump is original. Feels good to spin, no bearing issue and no mechanical seal leak. I have not removed for checking impeller clearances. do the coolant pump impellers wear?

    Coolant. Has had Nulon Ultra Cool which says it is good for all metal types in the engine. Block was fully washed out 5 years ago when engine was removed to deal with an oil leak between block and bell housing (can shaft welsh plug). Will do coolant flush this weekend and will change thermostat.

    What is involved in rebuilding the raw water pump? Never done that.

    Cheers
    Mick

    #41426

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    I have that data for the SMX and Sherwood pumps but not for the Johnsons on the Yanmars but I’m sure it’s out there. IMO, time would be better spent making sure that all is 100%. Have you ever rebuilt the pump? Cam? How old are the intake hoses, 15 seasons? Why not replace as preventative maintenance. Verify the intake is 100% free and clear. You did not report back as to your coolant side history? If you had the t-stat in hand I would have replaced with new. And flush the coolant side.

    #41415

    Mick Huestis
    Participant
    Vessel Name: Silly Blue
    Engines: 4LHA-STP
    Location: Brisbane
    Country: Australia

    Thanks Rob

    is there somewhere a bit of data that says what the unrestricted flow rate should be directly off the raw water pump?

    cheers
    Mick

    #41396

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    Just because the intake side of the seawater system can handle a garden hose flow means nothing as to possible restriction. That just means it’s not totally blocked which is obvious because you are simply running warm, not going into sudden overheat. To my point about the garden hose – Users of fresh water flush setups will collapse a garden hose simply idling at the dock.

    The pump flow rate is spec’d based on a max restriction on the intake side and a max psi downstream. If either of those go out of spec the pumps flow rate will go south.

    #41332

    Mick Huestis
    Participant
    Vessel Name: Silly Blue
    Engines: 4LHA-STP
    Location: Brisbane
    Country: Australia

    guys, another thing.

    What flow rate should the sea water pump have? 4LHA-STP

    when engine is cold I should be able to run at 1000 rpm for a minute with the sea water diverted into a bucket to measure flow rate.

    #41331

    Mick Huestis
    Participant
    Vessel Name: Silly Blue
    Engines: 4LHA-STP
    Location: Brisbane
    Country: Australia

    Hi Rob

    Thanks for the ideas.

    I have a seacock with basket strainer.

    The basket is clean.

    I have put a hose down the seacock valve to the inlet grate and at full pressure the water all flows out the bottom.

    I would have thought that if the inlet was blocked the hose would have backed up and overflowed the seacock.

    I’ll try your idea of greasing the top plastic gasket – never done that before so will give it a try.

    cheers

    #41327

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    You didn’t mention the raw water pick up under the boat or basket strainer or ???. What exactly do you have? Could it be getting restricted? My current boat has squid screens and if I just let the yard slap paint on them every year the flow would be less and less over time. Every season I slide out the screens and open the holes with an 1/8″ bit.. Also the intake hose(s) between the seacock and the pump needs to be checked that it is not failing internally or clogged with something. Do you have a basket strainer in the engine room? Have you checked, replaced or cleaned/greased the cover gasket. Sucking air could result in reduced flow.

    #41230

    Mick Huestis
    Participant
    Vessel Name: Silly Blue
    Engines: 4LHA-STP
    Location: Brisbane
    Country: Australia

    What is the best way to clean the engine block coolant cavities?

    I’ll do that too.

    is any cooling system cleaner ok, or is there a ‘best’ type?

    #41215

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    If all you said is as you say it, then you are down to a thermostat that is not working as you think, a seawater pump that pumps water but not enough, something else restricting seawater flow ( your elbow or ??) , OR an engine block that if filled with some kind of crud in some passages that are reducing coolant flow in some areas ( where the temp sender is ?) ….That’s why they make engine block cleaners..

    Remember, your engine is 20++++++ years old and Yanmar’s have always had coolant issues to do with gelling, etc., when the wrong coolant was used.?? ……………………..Don’t know for sure.. ………..Gauge calibration ???

    Let us know what to find..

    BTW, although 190F is 100% Safe ( and good) , it would be nice to know why the 5-10 F increase over the year or so………………………….Sorry, I do not think in C..

    Tony

Viewing 20 replies - 1 through 20 (of 25 total)

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