Help - Overheating

[dscar4u]

My friend has a major problem and you guys have been very helpful to me on my triumph so here it goes.

Let me lay a foundation. The boat is a hydro sport with a Johnson v4 130 hp both are 1995 models.
The last time he ran it would go for about 2 minutes and the overheat alarm went off so he shut it down but he said it did not feel hot to touch. ??? Anyway it has not been run in about 2 years. I brought it home last week and had a new impeller put in it. The tell tale was stopped up and they blew it out. It started right up and purred perfect. I went ahead ad replaced both temp switches thinking he had a faulty one giving a false alarm. I took it to the lake Saturday and it drove for about 3 minutes and the alarm went off. I shut it down waited about 20 minutes and then came back to shore. AS I neared the boat dock it went off again. Today I purchased an infrared temp gun and went back to the lake. I backed it in the water and left it on the trailer. I started it and the starboard side head stayed about 108 degrees. The port head rapidly climbed to 160 and I shut it down. So here is what I know.
1. There is water coming out the tell tale but not a lot and sometimes it takes a minute or 2 to start coming out. My Suzuki on my triumph shoots a stream but this one does not. Is that common.
2. Both thermostats have been removed prior to me bring the boat home. I shot water down both chambers and it came out the holes at the foot. I also shot it thru the thermostat hole and it came out as well. I thought maybe I had a blocked passage but it did not seem to back up.

Where do I go from here? I know it's the port side getting hot.

PS – this boat has always used in salt water and he never flushes it after use.

 

[Dave LeGear]

I would just go ahead and either test the T-stats in boiling water to make sure they do open as designed, OR just go ahead and replace them. The T-Stat also has to keep water in the block long enough for it to absorb the heat, so opening too fast and allowing water to flow though at a high rate of speed, is just as bad as not opening at all...

I would also start flushing this engine with some salt-away (use the search tool for more info) to help break up any salt and crud in the engine... Matter of fact, I would get a large plastic animal trough and lower the engine foot into it with quite a bit of salt away added to the cooling water and let it run for quite some time at idle (20 min or so) to allow it to get to FOT and circulate the salt-away and water mix many times through a hot block. Some of the cooling passages may be blocked up... I would also check the torque on head bolts (read the manual on the sequence and amount needed in foot pounds) and make sure they have not stretched from all the past overheats. I would also snug up any other loose bolts you may find on this engine... YOu could have a leaking intake that is leaning out the air fuel mixture which also causes engines to run very hot.

One last thing is the overheat alarm sensor may be giving a false signal. I would have it tested / replaced and make sure "all" the electrical grounds are clean and tight

Let us know how you make out

 

[dscar4u]

RE Puttershark

I have put new temp sensoprs in yesterday and i test them and they are working. THe t-stats are gone. I dont knwo how long he has run it without them. Thank for the infor on flushing i have never run in salt water so i am not to up on the things to do. I will do a search on it. Also i have just put in new head bolts last week and i did not torque them.

 

[wpschaef]

Torque.

Just a thought but if the head bolts aren't torqued correctly you will blow a head gasket and can do other damage as well. Good luck!

 

[BarryB]

Heat

Hi DS,

The motor is a V 4 and one side is hotter than the other.

PuterShark is correct about the thermostat. The thermostat slows down the water flow so heat can be moved to the water.

1. Remove the spark plugs and check if they look the same (left bank vs. right bank).
Check for overheating of the plugs. To see what a plug should look like, search some spark plug companies web sites such as Champion and NGK. They usually post photos of normal and not normal plugs.

2. If the plugs all look the same, there may be a blockage where the head gasket allows water to flow around the top of the head. Since the gasket may be a metal material, there might be corrosion around the water holes.

3. Look for an aftermarket repair manual to help in diagnosis.