2008 Suzuki DF300 pair overheating with exact same symptoms! HELP!!!

[HalesMarineServices]

I just bought a 08 Proline 32 with a pair of 2008 DF300Z and it has sat for 3 years and has only been run a few times in salt water. These engines have 34-35 hours on them. I just finished putting new water pumps, t stats, poppet valves, new water tubes and grommets, tune ups, oil changes, all filters, new cylinder head temp an exhaust manifold temp sensors. That being said, I am still having the exact same overheat issue it had from when I purchased the boat. I have Suzuki diagnostic software and cable so I can see the temp rising on the monitor. It takes about 2-3 minutes of running at 2000 rpm's to set overheat alarm or about 6-7 minuted at idle or just above idle. When run at 2000 rpm's it sets a gradient alarm. When run at idle it set cyl temp alarm. Temp reaches 210-220 pretty quickly and I am not getting consistent tell tale stream from either engine. I have run descaler mixture through both engines repeatedly with no change. Has anyone ever had this issue? I have been doing marine service for a long time but I am stumped where to look next.

 

[99yam40]

what descaler did you use?

may have to pull it apart if the passages are plugged up.

Are you sure the pump housing and impeller are the correct ones?

I have had some luck dropping lower unit , hooking up a water hose to the pipe leaving water pump heading to power head , open up water full blast with stats & stat covers out and injecting compressed air into the water going in to move things around, washing stuff out of bottom areas of motor.
but that was not on a susuki 4 stroke

 

[jbcurt00]

Hale
Dont post hidden links

Check your PMs

 

[HalesMarineServices]

What hidden link are you referring to???? I didnt post anything hidden or any red buttons jbcurt00!

 

[jbcurt00]

What hidden link are you referring to???? I didnt post anything hidden or any red buttons jbcurt00!

There was a link at the bottom of your post, I deleted it.

Perhaps you were unaware it was there or it was accidental. Either way, I removed it

 

[99yam40]

Bad gas, running lean, or timing being off might cause more heat, but would not affect tell tail flow

could it be that corrosion has eaten through something?

 

[clanton]

Remove the anodes from the cylinder heads, 4 in each head, you can see what the water passages look like. Waterpump change should include all pump parts including the housing.