Perkins 4108. Hard start. Possible Exhaust Elbow Problems

[SailnParadise]

I have a Perkins 4108 on a boat I recently purchased. Got the engine running finally and noticed after the third time doing a test run that the heat exchanger doesn't seem to be heating the water. There is also white smoke even after warm up. Have had to use a starting aid each time to get the engine running except when restarting within a few hours of shutting down. The water issue is only a recent issue as I tested the water after the first and second test run. Trying to diagnose what the problems might be but I am new to diesels and not sure where to start.

[marcjsmith]

Heat exchanger not getting hot..
Sea cock open, Strainer clogged, Raw water pump has broken impellers, sea cock blocked with sealife growth...


I’ve never had to use the thermo-start. Are you advancing the throttle enough? Is your battery fully charged, is the starter spinning the engine over fast enough? Do you have some air in the fuel line?

[SailnParadise]

Originally Posted by marcjsmith

Heat exchanger not getting hot..
Sea cock open, Strainer clogged, Raw water pump has broken impellers, sea cock blocked with sealife growth...


I’ve never had to use the thermo-start. Are you advancing the throttle enough? Is your battery fully charged, is the starter spinning the engine over fast enough? Do you have some air in the fuel line?

I have been using a 25amp/75amp charger/engine start when cranking. But the bottom does have a lot of barnacles. This effected the RPM until this morning when I scrapped it. I will dive again in the morning to clean the thru Hull and check the sea strainer. I will also replace the impeller and see if there is any improvement. I was considering doing an overhaul. But I am 50-60nm away from a viable yard so need it at least in a condition to make the trip

[Lepke]

The heat exchanger cools the water and is usually cool to the touch depending on the model.
If you don't have glow plugs, they help starting. Also a block or pan heater. If you have AC power, a hair dryer blowing into the air intake helps. Lay off heavy applications of ether. It causes a huge rise in cylinder pressure, too much breaks rings and then you need it every time.

A diesel starts by compressing the air above the ignition point of diesel. If the engine cranks slow, too much air escapes past the rings. Each compression stroke raises the temperature of the air and parts in the cylinder. 3 compression strokes should be enough to start a 4108. The higher the temperature of the engine and intake air, the easier it is to start. That's why glow plugs, block or pan heaters help older engines start.
If you or the last owner used ether heavily, you may have cracked rings. You may not need an overhaul just new rings.

One more remote possibility is the fuel flowing back to the tank between runs. Bleed the injector pump and check for air. White smoke can be steam or unburnt fuel. A cold engine doesn't atomize fuel correctly. Air in the injector lines or pump compresses instead of moving the correct amount of fuel. It can take many revolutions to push air out of the pump and lines.

[AlyeskaMaritime]

Originally Posted by marcjsmith

Heat exchanger not getting hot..
Sea cock open, Strainer clogged, Raw water pump has broken impellers, sea cock blocked with sealife growth...

Maybe I'm reading something wrong here, but if the OP is saying that the coolant is not heating, as opposed to overheating, then clearly there is no lack of raw water flow, but rather a lack of cooling moderation. I would speculate then that the thermostat is stuck open.

[AlyeskaMaritime]

Originally Posted by Lepke

The heat exchanger cools the water and is usually cool to the touch depending on the model.
If you don't have glow plugs, they help starting. Also a block or pan heater. If you have AC power, a hair dryer blowing into the air intake helps. Lay off heavy applications of ether. It causes a huge rise in cylinder pressure, too much breaks rings and then you need it every time.

A diesel starts by compressing the air above the ignition point of diesel. If the engine cranks slow, too much air escapes past the rings. Each compression stroke raises the temperature of the air and parts in the cylinder. 3 compression strokes should be enough to start a 4108. The higher the temperature of the engine and intake air, the easier it is to start. That's why glow plugs, block or pan heaters help older engines start.
If you or the last owner used ether heavily, you may have cracked rings. You may not need an overhaul just new rings.

One more remote possibility is the fuel flowing back to the tank between runs. Bleed the injector pump and check for air. White smoke can be steam or unburnt fuel. A cold engine doesn't atomize fuel correctly. Air in the injector lines or pump compresses instead of moving the correct amount of fuel. It can take many revolutions to push air out of the pump and lines.

^^^This!

[marcjsmith]

My heat exchanger gets warm, but mine is a bowman that combined with the exhaust manifold. some 4108's have the heat exchange combined with the ex manifold and some are separate units.

IMO if the heat exchanger is not heating the water, and he's talking about white smoke. could be indicative of an overheat situation which would lead me down the road of no water flow. impeller on the water pump is an easy check, as is the on board strainer. and to some extent with out going swimming, you could remove the hose from the engine seacock and use a tool to knock off any sea life living inside the thru hull. yeah it means opening the seacock and making a mess. but it beats swimming.

in conjunction with above I'd pull the ends caps off the heat exchanger and check the tubes for blockages and replace the coolant. and for good measure the t-stat.

all in under $100 and a few hours of work, depending on how difficult access is.

The 4108 does not have a glow plug. its what they call a thermo start. basically a diesel fueled flame in the intake to warm up the air.

if that solenoid is not working then you wont get a fuel drip to light and warm the intake.

[skipperpete]

Originally Posted by AlyeskaMaritime

Maybe I'm reading something wrong here, but if the OP is saying that the coolant is not heating, as opposed to overheating, then clearly there is no lack of raw water flow, but rather a lack of cooling moderation. I would speculate then that the thermostat is stuck open.

Once way back before wax pellet thermostats, the fail mode was indeed “stuck open”, but with modern thermostats the fail mode is now “closed” which usually causes an overheat depending on whether a bypass is incorporated into the circuit