2002 f15 yamaha 4-stroke over heating

[wesley meadows]

i have a 2002 f-15 4-stroke i bought used and was told it ran fine.it cools good when it is hooked to the water hose at the top of motor where the water hose connection is.but when it is in the water it pumps ok at idle but starts to get vary hot on the spark plug side.also stops pumping at faster speeds.i put a new oem impeller in it no change .i thought it may be the thremostat but there was not one in it.can anyone help me.i have ordered a new complete water pump kit to put all new parts in it to see if that helps.marina only had impeller at the lake.

 

[mdunn]

Re: 2002 f15 yamaha 4-stroke over heating

it cools good when it is hooked to the water hose at the top of motor where the water hose connection is.

Others will have more knowledgable info but that water connection at the top of the motor you referred to is intended only as a means of flushing when not running the motor. It will overeheat quickly if you are running it while connected there.
You either have to use muffs or a tank.

 

[hendu3270]

Re: 2002 f15 yamaha 4-stroke over heating

I've got the exact same motor and just replaced my water pump this weekend. When I took it all apart, I had several rubber pieces, (remaining bits of the impeller), jammed down inside the pump housing. I had to get my knife to clean them all out. In doing this, I also noticed that it looked like the little "channel" that water gets drawn through on the housing was deformed when it was cast at the factory. I had to slightly cut away some material to open it up some. Not sure if yours is the same but you might try these two things as well.

Once I put mine back on and cranked it up my oil light is now on. Great...something else to mess with. I just don't know if these little motors have an oil pump in them or not that could possibly go bad. Hope you get your water pump issue fixed.

Chris

 

[sdsaw]

Re: 2002 f15 yamaha 4-stroke over heating

I've got the exact same motor and just replaced my water pump this weekend. When I took it all apart, I had several rubber pieces, (remaining bits of the impeller), jammed down inside the pump housing. I had to get my knife to clean them all out. In doing this, I also noticed that it looked like the little "channel" that water gets drawn through on the housing was deformed when it was cast at the factory. I had to slightly cut away some material to open it up some. Not sure if yours is the same but you might try these two things as well.

Once I put mine back on and cranked it up my oil light is now on. Great...something else to mess with. I just don't know if these little motors have an oil pump in them or not that could possibly go bad. Hope you get your water pump issue fixed.

Chris

Chris,
When was the last time you changed your oil?
If you have a filter that is part of the drain screw, they tend to clog easily.
...And yes, they do have an oil pump.

Scott

 

[hendu3270]

Re: 2002 f15 yamaha 4-stroke over heating

Actually I haven't changed the oil yet. I bought it used a few months ago and the guys said he had just changed it, (the oil looks new and not at all dirty). I wasn't aware that there may be a oil filter as part of the drain screw. I'll have to look at that this evening. I wish it had a oil pump that didn't require taking apart the entire motor. Don't know that I want to break that far into the motor myself.

Sorry for the hijack wesley.

 

[scottfromoz]

Re: 2002 f15 yamaha 4-stroke over heating

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[Yamajoe]

Re: 2002 f15 yamaha 4-stroke over heating

Wesley u got hijacked, Flush the motor using either muffs and or with lower unit fully submerged in thrash can; use the top connect point to flush when motor is off, as there may not be sufficent water reaching the impeller, when this happens it will take a matter of moments to damage the impeller. Your motor should have a thermostat, get a new one fitted if it is missing and wait until you install the new water pump kit bfore runnig it again. If you haven't changed your oil for some time, do that too, as these motors "make oil" and oil gets too diluted with fuel and this causes problems starting with overheating. No is a good time to to a compression test and or leakdown test and post the numbers. If you have breached head gasket then this will cause your overheating as well. When you remove spark plugs what state are they in, black and oily, healthy tan, steamed clean? Good luck

 

[finlay]

Re: 2002 f15 yamaha 4-stroke over heating

you should not run the motor with the water going through the flush fitting under the cawl pan...because water does not get to your water pump... your problem will be ither under the power head or the water tube could have a hole in it...

 

[wesley meadows]

Re: 2002 f15 yamaha 4-stroke over heating

spark plugs are a light tan color they have only about a hour on them,i have 105 on top cylinder and 95 on bottom cylinder on the compression.oil is very clean gold color.i have a new complete water pump kit ordered,thermostat,oil filer and oil.i did see that the thin metal plate under the water pump housing was bent up on the thin side where the water comes up into the impeller.i am hoping this will fit it.how do you check to see if the hose has a hole in it
thanks
wes

 

[hendu3270]

Re: 2002 f15 yamaha 4-stroke over heating

here's a dumb question for you. how do you go about checking the compression?

 

[wesley meadows]

Re: 2002 f15 yamaha 4-stroke over heating

i checked it with a compression checker,you can get one at most all auto parts store.

 

[hendu3270]

Re: 2002 f15 yamaha 4-stroke over heating

i checked it with a compression checker,you can get one at most all auto parts store.

Thanks!

 

[Yamajoe]

Re: 2002 f15 yamaha 4-stroke over heating

subject to how you did the comp test, the compression is reasonable any lower than 90 will need closer look;that plate should not be bent and is most likely your problem, a new plate should come with your kit; with the pump off, remove thermostat cover, plug a hose to the water tube and very low pressure turn tap on, observe if water is pissing out in the exhaust housing, good flow exiting the thermostat housing is what you are looking for.

 

[wesley meadows]

Re: 2002 f15 yamaha 4-stroke over heating

thanks,got ost of the parts today hope to get resty this weekend hope get it fixed.

 

[wesley meadows]

Re: 2002 f15 yamaha 4-stroke over heating

i was checking to see if anyone can tell me how hot the spark plug side of this 15hp 4 stroke should get.it get pertty hot right now with the new water pump in it.it will sizzle water on the out side of it in about 5 min.is this about right

 

[Yamajoe]

Re: 2002 f15 yamaha 4-stroke over heating

Feel the water as it exits the pisser and from the exhaust ports, if its too hot to touch then you need to continue to find the source of the over heat. is the paint discolored or peeling in the area near you plugs?

 

[wesley meadows]

Re: 2002 f15 yamaha 4-stroke over heating

i ca touch the water ,the block area around the plugs is some light discolor to it,but it was already like that when i got it.

 

[wesley meadows]

Re: 2002 f15 yamaha 4-stroke over heating

i just want to thanks alhelp i got on fixing motor.got it fixed this is a good one.i put a new complete water pump kit ,thermostat ,oil,oil filter .fired it up ran for about 2-3 min starting to get real hot again on the spark plug side .so i removed the foot took a air hose and blew up the tube from the bootom and it felt restricked,so blew hard and something cam loose in side .fired it back up it started pumping a vey steady stream out ,so reved the motor up and a and bumble bee got pushed out of the pinky sixe hole under the cawlin in the back and water started to come from it in gear.so everything seams to be good now.thanks again
wes

 

[pine island fred]

Re: 2002 f15 yamaha 4-stroke over heating

Hate to dissapoint you guys but if you flush with the built in hose fitting without running the engine you are wasting your time. For 3 yrs. I flushed my F115 like a religion in spite of the mosquitoes and no-see-ems. Felt real good about doing it until I discovered there are no bleed holes to allow the fresh water past the thermostat. With the thermostat closed as it will be once cold water hits it, you get no circulation thru the block.
This past year I have been running my engine at idle for at least 10 mins. while on the hose fitting. So far no problems. Intend to post on this method if I find out I am doing damage, if so the next step will be drilling a few bleed holes in the thermostat disk to allow some water circulation. Will agree you are flushing the exhaust cooling section when you leave the engine off but my priority is flushing the whole power head. regards FRED

 

[athens1]

Re: 2002 f15 yamaha 4-stroke over heating

i have a 2002 f-15 4-stroke i bought used and was told it ran fine.it cools good when it is hooked to the water hose at the top of motor where the water hose connection is.but when it is in the water it pumps ok at idle but starts to get vary hot on the spark plug side.also stops pumping at faster speeds.i put a new oem impeller in it no change .i thought it may be the thremostat but there was not one in it.can anyone help me.i have ordered a new complete water pump kit to put all new parts in it to see if that helps.marina only had impeller at the lake.

Your 2002 does have a thermostat. The hose connection on the motor is for flushing only. Do not run the motor with out another hose connection to muffs to supply water to the pump. You might want to invest in a Yamaha shop manual for this specific motor. I did and it sure has come in handy. Thermostats are easy to replace and normally come with a gasket. If the engine overheats it will stop running as it has over heat protection.

If you run the engine without water to the pump via the muffs you can kiss the impeller good by. You must have two water supplies to run the engine or put it into a tank. However at nearly 100 pounds it is not an easy task.