1995 130 hp uneven cylinder temp issues, what is the cause/solution

[PG]

I just purchased this boat and am trying to get it ready for water and while testing in driveway with lower in testing basin. Initially I wasn't really getting water thru telltale so I remove tubing from nipple that attaches to lower cowl outlet to make sure debris wasn't obstructing it. So with it removed from nipple and left loose the motor is pumping really good but I noticed #1 cylinder highest on block was noticeably warmer than the other 3....... so I shut it down. Now it is hot but not so hot that I cannot hold my hand on block. I estimate probably 125-130?, all others are probably no more than 100?.

My first 2 thoughts are that maybe by leaving the tubing off the telltale nipple it not getting enough back pressure to fill the upper cylinder water jacket????

Or, maybe #1 carb isn't clean and only getting little or no fuel thus the cylinder isn't lubricated by the fuel oil mix.

Any ideas guys?

Is it possible there is thermostats for each individual cylinder and that one not opening? Forgive me I just got boat and haven't had a chance to purchase the service manual yet

 

[SilverSS07]

Re: 1995 130 hp uneven cylinder temp issues, what is the cause/solution

There are 2 thermostats located below the exhaust. They are a nightmare to get at. You can see the hoses going to them from each cylinder bank. You may want to check those but the other thing might be the water deflectors. You have to pull the heads to get to them but I would much rather do that than put in a set of thermostats lol. Here's a link with a pic so you can see where they are.

http://forums.iboats.com/johnson-ev...ater-deflector-tubes-water-jacket-355779.html

Also if you have an IR temp gun they're good to check the temp of the heads.

 

[PG]

Re: 1995 130 hp uneven cylinder temp issues, what is the cause/solution

There are 2 thermostats located below the exhaust. They are a nightmare to get at. You can see the hoses going to them from each cylinder bank. You may want to check those but the other thing might be the water deflectors. You have to pull the heads to get to them but I would much rather do that than put in a set of thermostats lol. Here's a link with a pic so you can see where they are.

http://forums.iboats.com/johnson-ev...ater-deflector-tubes-water-jacket-355779.html

Also if you have an IR temp gun they're good to check the temp of the heads.

I did a quick search, this is a 1995 130 hp motor and there are 2 thermostats and are at top of crankcase just above #1&#2 spark plugs. I will remove and inspect tomorrow to see if there is gunk in it and replace if necessary. .....

 

[boobie]

Re: 1995 130 hp uneven cylinder temp issues, what is the cause/solution

Silver, this a looper not a cross flow!!!

 

[PG]

Re: 1995 130 hp uneven cylinder temp issues, what is the cause/solution

Silver, this a looper not a cross flow!!!

Yes, this is a looper. ......

 

[SilverSS07]

Re: 1995 130 hp uneven cylinder temp issues, what is the cause/solution

Silver, this a looper not a cross flow!!!

Doh! My bad...

 

[175se]

Re: 1995 130 hp uneven cylinder temp issues, what is the cause/solution

you deff need to check temp,at top of head- the stbd side usually a little warmer. when running if you increase rpm to around 1800 motor should start to cool down.

 

[PG]

Re: 1995 130 hp uneven cylinder temp issues, what is the cause/solution

Im going to pull thermostats and clean them off. I was running motor in a tub with antifreeze water mix because its been cold here in NY and my hose wasn't working. Unfortunately due to an initial no start condition and decarbing there was alot of oil scum in test tank an I wonder if this might have gunned up that one thermostat.

 

[racerone]

Re: 1995 130 hp uneven cylinder temp issues, what is the cause/solution

Coolant must be about 6" above the water pump.---------Just covering the intake ports is not good enough.

 

[PG]

Re: 1995 130 hp uneven cylinder temp issues, what is the cause/solution

Today I filled the tank higher above cavitation plates and after a warm-up I noticed top cylinder warming more closely inline with others I revved up motor to 1800rpms and they all cooled really quickly to the touch and all ran even temp.

This motor has yet to have a seas trial but in the tank it seams to hiccup, pop and occasionally stall at idle. Does this sound like I need to pull carbs and clean out or just run a pony tank with high concentration of seafoam to clean them out and free any stuck needle valves and decarb the cylinders?

Or is this just the characteristics of the Looper motor?

 

[racerone]

Re: 1995 130 hp uneven cylinder temp issues, what is the cause/solution

When you are doing this test in a tank there may be too much exhaust in the air for a motor to perform properly.----Try a fan to present the motor with fresh air.---------Carburetors must be verified clean.-Any blockage can result in damage to the motor.------Remove the 4 carburetor drain plugs and see if there are greenish deposits on those plugs.----Install a new impeller too !!