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1989 evinrude xp 200 coolant and backfire at idle

johnsii97

Member
Im new to the site. I recently purchased a used Evinrude 200 xp. It was not running when I purchased it. It does have good compression, and after a new power pack, it's alive. However, there are a few issues i need help with.
Cooling.
I did replace the water pump. and checked the t-stats. they seem to open correctly at 140 degrees. however, the quickstart feture would not disengage, and at idle, sometimes it will jump back to quickstart. I was not very comfortable with the lack of water flow from the heads. so I removed the poppet valves, and diaphrams. Now I have waterflow almost as good as a Mercury. I then grounded out the white with black stripe wire that controls the Quickstart feature.I now feel better about the coolant system. however, can someone tell me the pros and cons on doing this?

idle skip. or sneeze
The other issue is the idle. I have a skip,(sneeze-backfire) in the idle. it runs perfect at W.O.T. , But I can't figure out the skip. I have noticed I have a spark in the starboard top carburator at times. carburators seem to be clean. so i'm not sure which way to go on it.
I have done away with the oil side of the VRO and premixing 50:1. to me, just safer with an 89 model.
any ideas? please help.

seems to be a great motor. if I can get the bugs out. with a little help
thanks
 
I think is is a mistake to run a motor without thermostats !-----You may need to make sure that throttle and ignition are properly synchronized. One carbureter's throttle plates slightly open will cause a miss like that.-----All throttle plates MUST be closed at idle.---The backfire may also be due to a lean condition and you should remove carburetors for cleaning.
 
Thanks for the reply. I will clean the carbs tonight. I did notice that it has air jets that are non adjustable.there are no adjustments to these carbs that i'm aware of. I will check the throttle plates as well. I would like for you to explain why it's a mistake to run without a thermostat. this engine was running pretty hot with the thermostats in. no warning alarm, but after testing, I was not getting any water from the heads. I tested the thermostats, and they were opening at 140 degrees. but still not cooling the way it should i think. I was unable to put my hand on the head without snatching it back before I removed the thermostats and diaphram gaskets. now, it runs warm. when i replaced the water pump, I flushed the cooling system to remove any obstructions. so I know the ports are clear. I also did away with the flow control. so it pumps from the water pump, thru the engine, and to the tail-tail. Maybe thats why I have a sneeze at idle. but it was doing the sneeze before as well. Now, if I throttle up to 2800 or so, it will not sneeze for a bit. but goes right back to the sneeze. if that helps any.
also, I don't know how long this motor was sitting befor i got my hands on it. I know at least a year. From the looks of the boat it was on, may have been many years.
 
Be sure to route your pisser hose up and over the top of the stbd. Cylinder head, that helps ensure that water is reaching its level to the top of the block.

If the heads have ever been removed or if the engine has ever been overheated you probably should pull the heads to inspect the condition of the water diverters (pieces of hose placed between the cyl's and outer block to route the cooling water flow).

Don't run without thermostats for very long..... find out why it's overheating and fix it right. Those are good engines, take care of it right.
 
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Just so you know, running without thermostats can cause the water to flow too quickly through the block without filling all the voids with cooling water. Go too long like that and you'll toast the voltage rect/reg. PRICEY!
 
because of jumping out the quickstart. right?
thanks. I may have to do that. I have heard of people doing away with the t-stats. but i sure don't want to mess it up. that's why I wanted some opinions. I am
 
Fix it !!---------------A common mistake is to remove thermostats.---------------As was suggested you should do some maintenance.----Pull the cylinderheads and replace those wee hoses ( deflectors / water flow guides ) -------------Proper maintenance costs nothing and it will save you a bundle in the long run.
 
I have been scratching my head. i tested the thermostats and they open. but. I don't get much water thru them.
also. one other thing was the coolant hoses the port had goes to the starboard head. the top of the block goes to the tail-tail. the starboard head goes to the left side of the flow control. the starboard block base goes to the right side of the flow control, and the bottom of the flow control goes to the tail-tail. correct me if I'm wrong as I have yet to find a manual with this information in it.!
 
One other thing maybe someone can explain. with the thermostat screwed into the diaphram, how does water get thru to the hose that crosses from head to head, and then to the flow control? Or, is that actually an intake from the flow control. I don't want to ask stupid questions. I'm no stranger to mechanical work. but this has thrown me for a loop. And if there is something wrong inside the heads, how am i able to get such a good flow with the poppet valves removed? Sorry to be difficult, just trying to understand. It seems OMC had made the cooling system more complex in those years. they went from no tail-tail to who knows what goes where...
 
I'm afraid I'd be wasting both my time any yours by attempting to explain it in text. A decent manual will have a water flow diagram, and once you study it a bit it'll all make sense.
 
Sorry , this model obviously does not have the water deflectors , they were on the earlier " crossflow blocks "----------Always post model numbers !
 
however, the quickstart feture would not disengage, and at idle, sometimes it will jump back to quickstart.
Either the engine is running a tad to cold or the head sensor is defective.......
I now feel better about the coolant system. however, can someone tell me the pros and cons on doing this?
The engine will run hot but the heads will be getting to much water and run cooler so it can overheat but never trigger a hot alarm......
I also did away with the flow control. so it pumps from the water pump, thru the engine, and to the tail-tail. Maybe thats why I have a sneeze at idle. but it was doing the sneeze before as well.
You cannot bypass this system unless you change to the different t-stats ,covers and springs......
I have been scratching my head. i tested the thermostats and they open. but. I don't get much water thru them.
Those heads run pretty dry and will be hot to touch...perfectly normal.
One other thing maybe someone can explain. with the thermostat screwed into the diaphram, how does water get thru to the hose that crosses from head to head, and then to the flow control?
Those are a combo poppet valve/t-stat, at idle and below 2500 rpm the water control valve is closed, which keeps water pressure on the back side of the thermostat diaphragms which in turn keeps the poppet/thermostats seated and t-stats allow water flow based on temperature. As throttle is increased the water control valve opens which relieves pressure from the back side of the thermostat diaphragms - this lets the poppets/thermostats lift off their seat which allows more cooling water to circulate..
 
OK. So I did more research looking for a diagram for the coolant hoses with no such luck. It seems to me that water is not supposed to come out of the thermostat ports on the heads. I don't see how it can get thru the diaphram. Possibly water is to enter the head there supplied from the lower block hose on the starboard side. On the sneeze. I cleaned and inspected the carburetors. After pitting it all back together. I can still see the backfire behind the top port side butterfly valve. Its sounds like a pop. I'm beginning to think it's a timing issue. It only does it at idle. I checked the plugs and gap. They are all clean and gapped around 35. Hope to make progress on it this weekend.
 
Thanks for the info. OK. So one question. What hose goes where on the flow control. I'm guessing here. But left side goes to starboard head right to the lower block hose and bottom to the tail tail??? Please let me know if I'm right or wrong....
 
Thank you. I did have it wrong. I am going to put it back together and head to the water to try it out. Run on the muffs first. After thinking about it. Really there is no water that comes out of the thermostat hose. It is an input instead.there must be another exit in the heads for the water to circulate. It makes since to me now. I guess I'm so accustom to those cool running Mercury. Motors.
Thanks again. I will post how it turns out. And hopefully get the other problem solved.( backfiring at idle).
 
All right!!!. So I just got back from the lake. The engine seems to be cooling fine. Thanks again for the help. The only other issue I have is with the sneeze at idle. Which is the pop in the carbs.
 
did u take carb back off and clean it agian? Ive heard these carbs are plastic and if they got hot they would warp and suck air?
 
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