hot fling

[sarice78]

i have a 1994 four winns fling

when i purchased the boat used it had and overheating problem.

i had the engine rebuilt, the carbs rebuilt, and the thermostats changed. it still overheated. i took it back and the mechanic backed it into his pond and ran the dog out of it. it still overheated. he finally filled the two ports (low pressure and high pressure) on the top of the drive with set screws. and it seemed to run fine.

then the battery went bad and i took it to a new mechanic (a lot closer to home). he found that the stator and the power pack were bad. he replaced these, but also found that the impeller was slightly hitting the wear ring. he replaced the stator and the power pack and reworked the impeller. after this it started great, but when i put it back in the water the engine was overheating again.

the 2nd mechanic suggested pulling the thermostats (practically new, but several years old by now) - i live in houston where they may not be needed. the problem is that the $50.00 thermostats are buried under the engine and cant be reached without pulling the engine.

my guess is that the original owner probably beached the boat and sucked crap into the intake.

1. any idea how to clean out the engine cooling channels?

2. any idea on how to pull the thermostats?

3. is there another engine that i can replace the original omc115 with. i know this is a stupid idea, but i like the boat and after several thousand $'s it's really

 

[wilde1j]

Re: hot fling

What engine (year and model)??? Is it an I/O or outboard? If I/O, you're asking the question in the wrong section of the board.

Very unlikely you need to "pull the engine" to change thermostats.

To clear debris, with the lower unit off, shoot water from a hose (or compressed air) up the water pump discharge tube.

 

[tashasdaddy]

Re: hot fling

wilde1j, the Fling is an Four Winns/OMC, joint venture, where the mounted a OMC powerhead and a jet drive together. this was the only boat this set up was used. so there are not many of use, familiar with the the setup. they are fun boats, when working properly.

 

[sarice78]

Re: hot fling

The engine is an OMC 115 turbo jet, and it doesn't have a water pump. The impeller provides the cooling water. The thermostats are configured on the bottom side of the engine with no room for access. I have the engine manual and the boat manual, but neither mentions how to access the thermostats.

 

[tashasdaddy]

Re: hot fling

you will probably have to pull the powerhead.

 

[ezeke]

Re: hot fling

The water (sand) filter is before the engine in the floor of the engine compartment. Make sure that the filter is cleaned regularly or the water will not reach the engine in adequate quantity to cool the engine.

Properly maintained, the filter catches most particulate that might otherwise cause cooling problems with the thermostat system.

BTW, The exact same TurboJet rig was used on many other boats including Boston Whalers. See the last chart at the end of this thread: http://continuouswave.com/whaler/reference/specifications.html

The filter assembly kit is part # 0437598, and the replacement filter is part # 0341965.

You shouldn't run the V4 crossflow without thermostats because it increases wear, carbon build-up and smoke, as well as not running as well.

If you do go into the thermostat housing, check the water deflectors in the cylinders while you have the engine out.

 

[sarice78]

Re: hot fling

ezeke:
i opened the filter and it looked ok. some slime and i smelled bad but nothing to really wash out. there was a screen but it was open at the bottom. looks like stuff could still flow though to the system. does this sound normal?
sr

 

[ezeke]

Re: hot fling

No, that's not normal for the water to get around the screen. The strainer is just that - it should keep the particles out of the engine so that they don't foul the thermostat system.

I think that the fact that the thing is clean after 14 years tells you that it is not and has not been working properly for some time.

Outboards have screens on the water intake to do the same job.

 

[SKEETR]

Re: hot fling

If the engine was rebuilt, correctly, you should have no debris in any cooling channel. Typically it is the head covers that fill with sand when beached. I agree that the heads should be pulled and water deflectors checked. As far as the termostats go, yup, pull the motor. When it's out open the drains on the adaptor and flush out real good.
The sand filter should have a basket type screen and should not be open on the bottom.

 

[sarice78]

Re: hot fling

during the last trip to the shop the mechanic took the boat out and said that one half of the engine was overheating and that the other half was ok.

is there any way that this issue could be cause by the impeller not pushing enough water through the engine or (given the lack of debri in the sand filter)is it more likely that there is a blockage in a hose or cooling channel thats providing less water through one side of the engine than the other?

 

[ezeke]

Re: hot fling

If one side of the motor is significantly hotter than the other, the most likely problems are that the thermostat on that side is blocked, or failing that, then one or more of the water deflectors has moved or failed.

Good shop practice requires replacing the cylinder head gaskets after an overheat, so you can examine the deflectors while you are doing that and replace them at that time if needed.

At any rate, pull the engine because the muffler is in the way of everything that you need to work on. You will need a new adapter gasket and a V4 crossflow gasket kit to do the job correctly. The kit for the thermostat system rebuild is Sierra part # 18-3673 and includes everything you need for that part.

You have to have a factory service manual to do the work - PN 502138. They are often on Ebay at a good discount. The 1995-1997 manuals are just as good for this job.

http://cgi.ebay.com/ebaymotors/OMC-...10109459234QQptZMotorsQ5fManualsQ5fLiterature

 

[SKEETR]

Re: hot fling

The four bolts on the nozzle assembly of the drive can be removed and separated to reveal the water pressure relief access screw. It sits at 12oclock and is about the size of a dime, can't miss it. Inside is a spring and a pressure ball. Wouldn't hurt to verify that there is no stick or junk in there. With a stiff pice of wire you should be able to run through to the impeller. Not that a blockage there would cause only half your motor to overheat. A manual will show all aspects of the engine in detail.

 

[sarice78]

Re: hot fling

so if i understand this right the overheating problem could be caused by:

1. the impeller not pushing enough water (although this might not cause the unbalanced heating issue with either side of the engine). *i need to add that i think the overheating issue may not be significant (as ezeke stated) because if i remember right the mechanic said the difference was like 20 degrees (if i remember right 160 - 180 *this may be off - i will have to check back with the mechanic).

2. the spring and a pressure ball at the water pressure relief screw could be clogged (although this might not cause the unbalanced heating issue with either side of the engine)

3. the screen in the sand trap filter could be bad because the bottom of the screen is open (although this might not cause the unbalanced heating issue with either side of the engine). * the sceen does look to be in good condition though.

4. the cooling channels could have debri (but not likely because of the sand filter). *this could be a likely cause for the unbalanced heating issue.


5. the water deflectors in the head or heads could be bad or misaligned. *this could be a likely cause for the unbalanced heating issue.


6. the head or heads could have sand in them (but not likely since the engine relatively speaking is still new since it is still in the break-in period - even though it has been several years since the rebuild because i have yet to have a really successfull run since the rebuild). *this could be a likely cause for the unbalanced heating issue.

7. a thermostat could be clogged or bad (even though the thermostats are relatively new). *this could be a likely cause for the unbalanced heating issue.

8. i shouldn't pull the thermostats even though i live in houston and a lot of boat owners i have talked to run their engines without thermostats.

9. i should pull the engine to access everything at once (even though some have posted that they pulled the exhaust and successfully reached the thermostats.

sorry, i know this is information overload and a long summary but i'm trying to get all this straight.

*also i did notice when looking at information on the sand filter that there was suppose to be a bracket holding the filter upright and plumb. my filter case is laying horizontal in the bottom of the boat. could this have an effect on the cooling and or the unbalanced heating issue?

last i would like to thank you all for your input because you have added information on this overheating problem (with this particular engine) that i have yet to read on any other forum. please continue to help because, it has become a hobby (some would say an obsession) to get this damn boat running, learn about the engine and the jet drive, and to spend some quality time with my kids and girl friend on the water.

sr

 

[ezeke]

Re: hot fling

"*i need to add that i think the overheating issue may not be significant (as ezeke stated)"

I cetainly do not mean to state or imply that overheating is not significant.

The fact that crossflows tend to run hotter on one side is common, but does not indicate that they are overheating, simply that they are not at the same temperature. If the difference is large or if one side is normally a lot higher than 143? F, that's a problem.

You cannot hold your fingers on the cylinder heads of an overheated crossflow for a three count, but you can always do that on one that is cooling properly.

If the warning horn sounded or if you find the paint blistered or discolored then you have overheated and that is always a problem to be taken very seriously.

As indicated, the filter is a basket filter and all water running to the engine should be strained by the filter.

 

[tashasdaddy]

Re: hot fling

are you running in fresh or salt water?

 

[SKEETR]

Re: hot fling

The water filter should be mounted and plumb thus allowing water to circulate above any collected sand and for ease of removal. These filters only remove larger particles even on a filter with an intact basket. If the filter was sitting sideways you would get a slug of sediment each time you fired up. Could become a problem. But it is not so much the sand that causes problems as much as the larger chips of gravel. With a non functioning filter laying sideways you are pumping everything into the motor. Gravity will catch alot of this gravel with a plumb filter housing. The small bits of gravel can be large enough to wedge themselves between cylinder walls and can be removed when you inspect your diverters after pulling your heads. However they can also wedge themselves into an open thermostat keeping it that way.

 

[SKEETR]

Re: hot fling

are you running in fresh or salt water?

Not to mention what kelp stew would do after chewing thru a patch of the stuff.

 

[SKEETR]

Re: hot fling

As far as the water pressure goes on a jet drive, as stated, if you have forward thrust you are pumping water. Factors that decrease water pressure are; the condition of the trailing blades of your impeller, the condition of the stator vanes (especially @ water inlet port), overall fit of impeller inside wear ring .05 max. I would not reccomend these inspections without a factory manual.

BTW your impeller retails for $700. If it is bent take it to a prop shop for repair.

 

[sarice78]

Re: hot fling

where are the stator vanes?

 

[SKEETR]

Re: hot fling

The impeller shaft housing (stator) is supported by them. To check the area of concern the impeller needs to be removed.