overheating issue p200trlq

[greatestfisherman]

Hi All,
I just had my carbs cleans and was in the mist of readjusting my idle screw... my motor is a 1992 Yamaha pro v p200tlrq... I took it out this morning and was running fine for a few minutes then the overheating alarm went off.... the water pressure is fine (new impeller)... the thermo was replaced last year with new gasket... it ran fine all year last year... im assuming the issue is carb related since it just started after the carbs were redone.... can an over loosen idle screw cause too of a rich mixture thus overheating the motor? service manual stat 1 1/8 - 1 5/8 turns.... i had it set to 2 for the top carb and 1 1/2 for mid and 1 for bot... with this settings it seemed to idle fine and I don't think its too fuel efficient... after the alarm went off, I let it cooled and readjusted the screw to 1 1/8 for both top and mid and 1 for bot... ran it for more than a few minutes and alarm did not go off... can someone verify my assumption or enlighten me.

thanks in advance...

 

[Capt Ken]

Re: overheating issue p200trlq

Short answer, no. It was just a fluke.

 

[greatestfisherman]

Re: overheating issue p200trlq

Short answer, no. It was just a fluke.

fluke...???

well today back from work I took apart the thermostat just to get a piece of mind and the passage is nice and cleared as I thought... I open the thermo housing and ran the motor on muffs (idle) and notice that no water was coming out of the area... however, I did flush the port with water and it came out of the lower unit like a flood which I assume is a good thing... (meaning the ports are not clogged )...

I just hope this fluke incident don't come back and haunt me when I go offshore fishing at the islands...

 

[greatestfisherman]

Re: overheating issue p200trlq

update.... motor still overheating... noticed that its overheating only on high rpm and when running for few minutes or so... i just changed both thermostats and clean the prv (poppet)... I also did a flush using a barrel ful of water with some corrosion cleaning agent... i only put alittle in the barrel and ran the motor for probably 10 mins... after, i did another barrel of clean water fresh to flush any cleaning agent from the motor... I hope this resolves the problem...

while flushing, i noticed the water coming out of the exhaust port while cold start and after the motor warmed up, not so much... I was also trying to pay attention of the heat from the powerhead... sometimes it hotter than other times... is this normal?

 

[greatestfisherman]

Re: overheating issue p200trlq

anybody? bump

 

[greatestfisherman]

Re: overheating issue p200trlq

another observation... i never had overheating problems until i redid the carbs... its it possible that the idle screw is not set properly causing a lean burn at high rpm thus overheating it? now that i think about it, the manual calls for 1 1/8 to 1 1/2 for all 3 carbs but i have the bottom carb set to only 1... i think this is why its overheating at high rpm (lean burn)... when i get home from work, will reset that carb and test it out when i have a chance...

i still have not had a chance to test it in the pond due to weather.

can someone please explain to me the carb placement? I notice when i was adjusting the idle screw on the top carb, it was making a difference in the low rpm range... i tried adjusting the bottom carb and it made no difference... can i assume that the top carb is for low rpm, mid for midrange and bot for high rpm?

thanks,

 

[99yam40]

Re: overheating issue p200trlq

each cylinder is fed by a carb so no, adjustment for idle on one carb will not affect other cylinders and pilot(idle) screws should not effect high RPM fuel mix.

It is like having multiple one cylinder motors tied together, so you need to make sure and follow service manual steps for link and sync every time you reinstall the carbs to make sure all are in sync with each other

 

[greatestfisherman]

Re: overheating issue p200trlq

I C... KINDA OF THOUGHT THAT WAS THE CASE TOO... but explain to me this, when i was adjusting the idle rpm, the bottom carb had no effect what so ever... i even tried closing off the valve all the way and it did nothing... it did not stall the motor...unless the fuel in the bowl kept it going but that does not explain the air ratio... only by adjust the top and mid carb was i able to get the rpm to 6 - 700 rpm... prior to the carb rebuild, i had never had any issue with overheating or timing... which makes me want to believe my issue is carb/fuel related???... any ideas? Ill go ahead and do a link and sync just incase...

 

[99yam40]

Re: overheating issue p200trlq

get back to us when you have done the link and sync and adjusted thing as the manual calls for

 

[greatestfisherman]

Re: overheating issue p200trlq

update... weather was crappy and was not able to test run... however, i did run motor on muffs after the link and sync (idle) and it overheated... while overheating, i noticed that the thermostat housing was very hot which leads me to believe its something related to that... under observation, it didnt seem like enough water was being pumped up there which usually mean impeller or the muffs not feeding enough water... i then took off thermostat housing and ran motor in a barrel of water and notice that water was being pumped fine into the housing... while idling, squirts of water can be seen pumping from the hole in the thermostat housing area and under higher rpm, the housing will flood with water... another observation, i made was that under alittle load, i noticed that water was being released from the exhause port which comfirms that the poppet is working correctly... can someone just verify that all this is normal AND SHOULD BE HAPPENING UNDER THE OBSERVED CONDITIONS...

TIA

 

[greatestfisherman]

Re: overheating issue p200trlq

update... was able to take boat out for sea trial and ran boat for more than 20 mins around 4700 rpm and no overheat... block was cool enough to touch... on idle, boat seem to run hotter than when in high rpm...

if my understanding is correct... when in high rpm, the thermostat will open from the hot water and so will the poppet due to pressure allowing more water to flow thus cooling the engine off... during idle, the thermostat is close so is the poppet to allow the engine to warm up faster...

this is exactly what happened under my observation... so far so good... this sunday is striper fishing season and off the the island... i hope i make it out there lol... will keep everyond updated.

 

[greatestfisherman]

Re: overheating issue p200trlq

hmmm still no answers... well ill keep updating this just incase someone out there is experiencing this same issue...

motor is still overheating... intermittently overheating... some days it runs fine and some days it decides to overheat... I decided to start from scratch and follow the basics...

I pull the lower unit off to check impeller and it looks like new... tested the thermo and it opens as it should on high heat... cleaned and reinstalled poppet... flush motor with simple green to remove any salt, corrosion etc... will be going out this week for fishing season again hope it works...

question, the new poppet vavle is a dome shape. Is the dome side suppose to be sitting against the spring or against the grommet against the head....

thanks,