Clean out internal cooling tubes?

[bigdogg1]

I have 3 symptoms that I am trying to remedy:

The motor cowling seemed hotter than typical after recent outings
The telltale seems less than usual
The motor is running a bit rougher

I have put a pipe up the telltale to clean out any junk. I have replaced my impeller/housing/water pump. Removed and replaced the oil and oil filter. Removed and replaced the fuel/water separator. I just removed the two thermostats and water-tested them. They opened at ~ 140 deg which is within specs.

Before I put the thermostats back in, is there any value in running either salt-away or a vinegar solution, or simply warm water down the tubes that are exposed with the thermostats removed.

Any other tips on cleaning out the cooling line?

Thanks

 

[tubber]

I sucked up the bottom at mcdonald launch and had similar poor running plus overheat alarms.
I idled in my pickle barrel with a cup of saltaway for several hours a day for three days.
I did a last trip to White lake and problem seemed gone, but didn't go high speed very much.
I changed the thermostat anyway this spring. Running well touch wood.

 

[gungadin]

I have 3 symptoms that I am trying to remedy:

The motor cowling seemed hotter than typical after recent outings
The telltale seems less than usual
The motor is running a bit rougher

I have put a pipe up the telltale to clean out any junk. I have replaced my impeller/housing/water pump. Removed and replaced the oil and oil filter. Removed and replaced the fuel/water separator. I just removed the two thermostats and water-tested them. They opened at ~ 140 deg which is within specs.

Before I put the thermostats back in, is there any value in running either salt-away or a vinegar solution, or simply warm water down the tubes that are exposed with the thermostats removed.

Any other tips on cleaning out the cooling line?

Thanks

When you removed the thermostats, you should have been able to determine the amount of salt built up on the inside passages, The amount of buildup you see will determine your next step. If there only a little, then running salt away may help. Leave the thermostats out while running salt away. If there is a lot you may have to remove some external parts to get to the cooling passages that may be plugged. Also keep in mind that the motor (you have not indicated make and horsepower) may have internal zincs that have corroded away and may have fallen from their installed location and are now blocking some cooling passages

 

[bigdogg1]

When you removed the thermostats, you should have been able to determine the amount of salt built up on the inside passages, The amount of buildup you see will determine your next step. If there only a little, then running salt away may help. Leave the thermostats out while running salt away. If there is a lot you may have to remove some external parts to get to the cooling passages that may be plugged. Also keep in mind that the motor (you have not indicated make and horsepower) may have internal zincs that have corroded away and may have fallen from their installed location and are now blocking some cooling passages

Thanks, Yamaha F250 TXR. Just under 400 hrs.

 

[gungadin]

You appear to have very little salt buildup, I would just run salt away through the external flushing device. I have found that leaving the salt away in the passages overnight and then flushing again the next day beneficial. Keep in mind that small chunks may break off and plug the tell tale passage. Also do not run the engine when using the flushing port. When you pull the leg you can look up inside the housing and see the build up as well. Don't forget to grease the splines at the top of the shaft.

 

[bigdogg1]

You appear to have very little salt buildup, I would just run salt away through the external flushing device. I have found that leaving the salt away in the passages overnight and then flushing again the next day beneficial. Keep in mind that small chunks may break off and plug the tell tale passage. Also do not run the engine when using the flushing port. When you pull the leg you can look up inside the housing and see the build up as well. Don't forget to grease the splines at the top of the shaft.

Thanks. Tube looked good. Splines were greased and fit back in rather nicely. Saw a YouTube where a guy used a strap to help support the weight when fitting it back. Game changer!

 

[profisher]

Get one of those cheap digital infra red temperature readers. It will confirm if your engine is in fact running hot. Bring it up to temp and check the head temps

 

[bigdogg1]

Get one of those cheap digital infra red temperature readers. It will confirm if your engine is in fact running hot. Bring it up to temp and check the head temps

Thanks PF. I am a wits end on this one. I may be chasing 2 unrelated issues (or not). Motor has gone from running rough to hardly able to start and only runs above 3500 with muffs on in the driveway. At the RPM, the telltale is still sporadic so not sure if the rough running is related or not. Here is what I have tried:

Removed lower end and replaced impeller - housing was in great shape
Replace fuel/water separator - no evidence of water in clear bowl or in filter body when drained.
Removed and tested thermostats - operate under proper temp
Drained and replaced engine oil.
Ran system multiple times with Saltaway
Ran thin wire up tell tale looking for blocks - none evident
Inspected fuel filter inside cowling - clean and no debris or water
Compression tested all 6 cylinders - within 5% of each other and at same spot when surveyed 3 years ago
Inspected all visible lines and wires around engine block

Beginning to think it is the high pressure fuel pump (although doesn't really address the telltale issue

 

[profisher]

Get insulted plyers and pull plug wires one at a time while the engine is running on hose. If engine rpms drops and it runs even rougher that cylinder is firing...if no change you have a dead cylinder...no spark.. Don't buy parts or change things until you find the problem..or you will chase it in circles.

 

[bigdogg1]

Get insulted plyers and pull plug wires one at a time while the engine is running on hose. If engine rpms drops and it runs even rougher that cylinder is firing...if no change you have a dead cylinder...no spark.. Don't buy parts or change things until you find the problem..or you will chase it in circles.

Thought about doing that but can't even start it now unless I engage the warm up throttle and start at 3500+ rpm from cold.

 

[profisher]

Sounds like a fuel problem then if you need to advance the throttle that much to get it to fire. It would start easily if only down a cylinder with no spark. If fuel injected does it have proper fuel pressure at the injectors?

 

[bigdogg1]

Get insulted plyers and pull plug wires one at a time while the engine is running on hose. If engine rpms drops and it runs even rougher that cylinder is firing...if no change you have a dead cylinder...no spark.. Don't buy parts or change things until you find the problem..or you will chase it in circles.

Quick update, still looking for the Gremlin - removing plugs 1, 3 and 5 (Starboard side of engine) makes no difference), They are offline. Engine is only running on 2,4, and 6 (Port side).

 

[Corey_lax]

Does each side have its own coil?

 

[bigdogg1]

Does each side have its own coil?

Going to look at that after work tonight. Thanks

 

[prodjsaig]

Also check your coil drivers for proper resistance. I had a bottom driver well below spec a .78 ohm when it was meant to be .99 +/- 3 ohm.

 

[prodjsaig]

if youre pulling plugs. but i would say check over the cooling system. have you done your poppet valve?

 

[Charlie415]

Also check your coil drivers for proper resistance. I had a bottom driver well below spec a .78 ohm when it was meant to be .99 +/- 3 ohm.

3 ohms or 0.3 ohms? Seem like a large tolerance.

 

[prodjsaig]

.3 ohm sorry. The bad driver was .78 way out

3 ohms or 0.3 ohms? Seem like a large tolerance.

 

[profisher]

Does that engine have a troll mode where cylinders cut out by design to save fuel and drop rpms? If not then you have a ignition problem for sure. On many motors triggers coils under the flywheel run multiple cylinders...on my Yami there are 2 trigger coils sharing duties on the 6 cylinders. I have replaced one in the past...had one on my 9.9 go as well.

 

[bigdogg1]

Does that engine have a troll mode where cylinders cut out by design to save fuel and drop rpms? If not then you have a ignition problem for sure. On many motors triggers coils under the flywheel run multiple cylinders...on my Yami there are 2 trigger coils sharing duties on the 6 cylinders. I have replaced one in the past...had one on my 9.9 go as well.

Thanks all. The boat is sitting at a shop right now as I decided to take it in to a respected shop. I am going to head there tomorrow am for an update and provide some carefully worded direction based on these inputs. I was poring over my service manual and kept coming back to those coils.

Do not think I have a troll mode - never seen any indication of such a beast - do they just drop rpm's on their own?