Which diesel engine make and model? ??
Universal 5432 / Kubota V-1501
How many hours? Do you have the previous owner's maintenance records? What is the compression of each cylinder?
Unknown, judging from condition of engine, several thousand would be my best guess. No records. No idea but there is some blow-by.
Is the noise constant or does it change with RPM? Does it change in frequency or intensity? Is it different immediately after startup compared to once the engine is at operating temperature?
Sound is present immediately on startup. It increases in speed with rpm's but does not get any louder. frequency and intensity stays pretty consistent. It does not change when engine gets warm.
Do you have/use pre-heat ?
Glowplugs? yes. It takes two attemps to start with glowplugs. I hold in for 15 seconds, attempt to start. It wont until I hold glow plug button in for another 15 seconds and then starts right up.
Do all 3 cylinders fire up instantly if you restart it when warm?
4 cylinders. Yes starts back up within 2-3 seconds of cranking when its warmed up.
Does the engine make rated RPM at idle and underway (no wind) ?
Not 100% sure there is no rpm gauge, but i know what 2500 rpm's sounds like in cars (drive stick shift for years) and i can get engine to that rpm based on sound easily. It sounds like it goes closer to 3k rpm if i advance throttle full open.
Are there any fuel leaks on the engine?
none visible. i always have my head in engine bay. no fluids are leaking.
With the engine running, remove the dipstick. Do you feel pressure? Is there enough pressure to blow the dipstick out? A little pressure is normal but pushing the dipstick out is not.
good question. the dipstick does not move. when i check oil its secure in its holder. i will check this weekend with it removed.
White smoke on startup is common for many marine diesels. Some owners have difficulty distinguishing between grey and white smoke.
this is plumes of white smoke. well beyond normal. it has that unburnt diesel smell. as soon as the engine comes up to temp and #1 piston begins to detonate fuel, white smoke immediately goes away. If engine is warm and i restart, #1 piston fires normally and there is no smoke.
For white smoke that persists for more than 30 seconds after startup, I'm suspecting:
• Damaged Injectors
• Faulty Injection Timing
• Damaged Crankshaft Keyway
• Damaged Timing Gear
• Low Cylinder Compression
• Damaged Rings or Cylinder Liners
• Water mixed in the Diesel Fuel (Cracked Head Gaskets, Cylinder Head or Block)
• Damaged Fuel Lines
• Low Fuel Pressure to the Fuel Pump
• Damaged or Incorrect Fuel Pump Timing
I wondered the same about injectors. This was the first thing i was going to address. I have a shop that can re-build them. a project that is coming up soon.
Does your engine leak / burn coolant?
no visible leaks. I need to check and pay closer attention but i dont think its burning coolant. i cant say 100% though.
The knocking sound that is present in all diesels is due to the rapid combustion once the mixture reaches the combustion point. This is why diesel engines are built much more rugged than gas engines. Some things can cause that combustion to be more sudden.
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1. Incorrect timing. Timing the injection pump to the engine is a fairly technical job, best left to your mechanic. I would suspect this if the noise was new/changed and someone had just reinstalled (incorrectly) the injection pump. Most injection pumps will benefit from a service around 4000-5000 hrs.
2. Clogged / worn injectors. Cause a poor spray pattern and a less then ideal combustion. Injectors should be serviced every 1000-1500 hrs. Adding the right fuel additives at each fill-up goes a long way to extending the lifespan of the injectors and reducing wear in the injectors / injection pump. This is especially true in North America where we have pretty poor diesel compared to Europe.
good to know. i only added a can of Seafoam a couple of seasons ago. I have not added anything else.
3. Bad fuel. For diesel we want Cetane (the opposite of Octane for a gas engine). Try a cetane booster in the fuel and see if it changes things at all. Have both fuel filters been changed?
good to know. Its been a couple of seasons since filters were changed, but the sound/problem was present before i changed them. new filters did not affect the sound, but they are due for replacement this season with fluid changes as well. i have not used the boat much the past couple of seasons.
4. Valve adjustment. Typically required every 1000 hrs for a small diesel, very often overlooked.
I adjusted them a couple of seasons ago. they were a little out but not drastically. it ran slightly better when i adjusted them. one of the valves above the #4? piston (piston opposite side of flywheel) is loose in its guide/seat and can be wiggled from side to side slightly.
5. Piston/rod slap, bent rod, etc.... This would require a partial rebuild.
which i probably wont do. i'd rather run it until it dies and save that money for a new BETA.
6. Bearings ... I'd be shocked if the bearing were worn out, unless the engine was severly mistreated.
i get the feeling the previous owner (who i never met) did general maintenance on all systems, but he suffered a severe head injury and the boat was left neglected for an unknown amount of time. i suspect a few years possibly. engine looks like it was pretty neglected at some point, although that may not mean it was mistreated. i dont know for sure. it was not in good condition aesthetically.
7. Engine mounts ... they will only work properly for about 1000-1500 hrs ... have they been replaced? Is the shaft aligned to the engine (shaft coupler gap should be 0.005 in or less).
definitely need replacing, but shaft is tight in cutlass, no movement of engine that i can tell. does not excessively vibrate although there is some vibration.
Can you narrow down where the sound is coming from? Does it change if you are in gear or not?
no change to sound if in gear. it just gets faster or slower depending on rpm. im absolutely convinced its coming from the head or lower in the engine. its too loud to pinpoint. im thinking of buying an engine stethoscope to try and narrow down closer. at first blush i feel like its in the lower half, no the head but i cant say with certainty yet.
How to troubleshoot:
a. Go simple/cheap to more complex/expensive
b. Use good lubricity and biocide additives at each fill-up
c. Check engine/shaft alignment and age of engine mounts
d. Measure compression for a warm engine
e. If you have no maintenance records, get the injectors serviced and the valves adjusted
f. If none of the above makes any change, I'd look at the injection timing / fuel pressure
g. After that, you're into a partial rebuild
good to know. i will be starting with the injectors. i feel like they absolutely need to be looked at.
.... you need to find yourself a reputable mechanic .... The cost of an engine swap is roughly double the cost of the engine itself when you figure haul-out, exhaust/plumbing / engine bed changes and all the other small things you'll pick up and want to address at the same time. It's best done out of the water to realign the shaft strut to the output shaft.
i can do the swap. its something i would feel comfortable doing. cutlass bearing, aligning, mounts, exhaust, wiring etc...etc is all something i feel like i could do. much of it i have done i just never have torn into an engine before. rebuilding an engine would be well beyond my ability, but all the peripheral stuff i have tackled before. i checked into rebuilding this engine a few years ago and decided it was not worth the time. much of the parts are difficult to get or becoming extremely scarce or non-existent. the engine is 1980 engine. im getting a price on a BETA 35 with transmission this week just out of curiosity, but expect it to be around 8k shipped. BETA 35's without tranny are going for 4k. im hoping to maybe get an engine next season or following.
