hot upper cyl 85hp v4

[Dali30]

Dont remember cyl nr,but the upper one on right side gets damn hot compared to the three others. I been told a time ago that bor and mount a nippel to let air pockets to get out,beacause this one doesnt have control-pee installed from factory,but the casting in blockside is ready to be borred so ill go a head and do that before i try this on water today or tomorrow,depends on trailer is avaliable,but now its ready and im exited for this one. motor is johnson 85esl73m,boat is 540cm silver viking sport.

 

[emdsapmgr]

A non-existant telltale should not be a reason for a single cyl overheat. I'd pull the starboard head and check the placement of the water diverter by that top cyl. Also pull the head cover off the starboard head an see what debris may be stuck inside the head cooling passages.

 

[Dali30]

should have added that,it has been rebuildt and cleaned. beacause cyl nr 2 is the highest one,its logic it gets hotter beacause of air pockets since the absent of tell tail from factory. Made this thread to hear if someone have same engine and done the same? im sure this will fix my "problem",its not like its overheating,but the cyl is clearly hotter than the three others wich is lower.

 

[schematic]

I would highly advise you to pull the head and inspect the deflectors. When they get old they can swell up and block off cooling passages.Could also use head gaskets by now as well.....

 

[Dali30]

is deflectors the bits of black hose wich sits in water cannels?

 

[schematic]

yes. The fail in 2 ways.....they swell up and plug passage ways, or the get free and travel around and plug passage ways.

 

[schematic]

No Title

good vs bad

 

[Dali30]

as i think,there where no deflectors in the upper cyl. what are they mission?

 

[schematic]

There mission is to ensure a equal water flow around each cylinder. There is 2 per bank. One in the middle, and one at the bottom. If the one in the middle is as shown, it can cause a "hot spot" area. There is also a bleed hole behind the one of the deflectors (about 1/8" diameter) that plugs with debris. May need to be cleaned or drilled out.....
Wouldn't hurt to clean the carb for that cylinder as well. Hate to find out you were running lean causing overheat.....

 

[Dali30]

ill check tose deflectors out,carbs and everything else is cleaned and replaced. thanks.

 

[Dali30]

as i pulled both heads off i see no deflectors,the headgaskets does not have holes to match these deflectors so i had to bore two holes in each gasket,no prob but thats why i didnt bother buy new ones in winter while i changes gaskets and stuff. should have new deflectors in mail by friday. A buddy gave me four old deflectors,but they dindt fit,like they had dry out and lost size and not sitting firm,in the garbage they vent. I noticed some small metal fragments on top of pistons on two cylinders,as i looked at it,i should have rounded the edges of the exhaust ports beacause they where sharp as he...or is the cause more likely lack of 2-stroke oil in gasoline??

 

[emdsapmgr]

Small metal fragments on the piston crowns could be the remnants of the upper ring of the piston. Do you also have pits on the face of the head? You can check the piston to see if the top ring is still intact. The piston will appear somewhat loose in the cyl and it can be moved around in the cyl (by hand) so that you can peer down onto the top ring. (flashlight is helpful,here.) Let us know what you observe.

 

[Dali30]

ok,no pits on head and yes the pistons does move a bit when i holds on top and "shakes" them,but that seems normal for a used two-stroke. It has 9bar pressure on all cylinders. those sharpy exhaust ports should be taken care of with a dremel,ill bet that is reason for the small metal fragments?

 

[emdsapmgr]

At this point, a picture would be helpful..

 

[Chinewalker]

There should be no holes in the cylinder head gasket for the deflectors.

 

[Dali30]

then i see no point in having deflectors ther,if i not had bore holes,the gasket will seal and block deflectors. the point is water to flow thru so holes must be made for them to function. remember water flows from the heads.

 

[emdsapmgr]

There is no water that flows through the holes in the deflectors. The deflector itself is like a dam, or a plug- it diverts water around the cylinder.

 

[Dali30]

what,damn i did never see that coming! my logically thinking got a stint hahah.. so.. basically incoming water hits this deflector and diverts beam in two,and kind of wrap the water around cyls? well the lokal dealer could not get me those defl,he suggested me mount heads and try it since making a pee beam gives it better water cirkulasion. all cyl are now equal varm after doing this. enigne seems responsive and strong,but after about 5min testing on water,it suddenly started 'piiiiiiip' from the control unit when i hit full throttle, (evinrude powerpilot) i stopped and pulled it in shore. Does someone knows who have this stock new somewhere? ofcourse old ones where dried up and rockhard from an old parted engine. i could order from net outside my country norway,but have to wait about 4 weeks to finally get my hands on them. Any tip for me to get these quick guys? i also need a starter-motor,it slipps and last test it sounded like it was burning/melting inside when i turned key to try start. deflectors and starter-motor is needed fast.

 

[Dali30]

....but since no water flows thru deflectors,if i can get a hold on some hoses that have the same outer diameter at the local hose-shop,they can be used without consering how big of a hole this replacement hose have? waht are your take on that emdsapmgr?

 

[NCmiller]

Dalia30, the water deflectors are available from any BRP dealer. I recently ordered some from boats.net. My 1985 90Hp was running too hot around the block area, heads remained relatively cool. In troubleshoot the problem, I pulled the bypass hoses from the bottom of the heads to the thermostat housing to observe the water flow. Right off I noticed that the STBD side had reduced water flow, about 50% less. After pulling the heads I found that the deflectors had collapsed and lodged in the water passages. Upon further inspection I found the thermostats stuck open.