963b

Not sure what drives you have but mine areTRS. My pickup tubes are in the bottom of the hull. I have a shut off valve between the garden hose hook up and the pick up tubes. If you have a setup like this, could be the valve isnt all the way open??? Dont give up yet, could be something very simple

BY U BOY

check to make sure the barbed fitting tht scews into the riser is not screwed in to far. that could easily be the problem. also pull and flush all the hoses your self it may not have been done by the shop.

NEVER - SATISFIED

I had a friends boat with the same problem. Ran cool on the hose and at idle but would heat up quick at higher rpms. There is a fitting in the gimble housing that brings water from the outdrive the large hose hooks to it and goes to the inlet side of your seawater pump. That fitting was almost closed off with buildup. Let enough water through at idle but starved for water at cruise speed. Just something else you may check good luck...Dean

jayhawk261

I had a friend with a set of Stainless Marine manifolds that did the EXACT SAME THING almost word for word melted rubber hoses and all. Our problem was the outlet fitting at the front of the starboard manifold was too long and tightening it up actually bottomed it out on the inner manifold. We pulled the fitting and cut it down. After that, no more problem. I don't know if the Imco manifold is similar in design to the Stainless Marine, but the problem sounds way too familiar! Check that all of the fittings have clearance against the internal surfaces.

stevesxm

first.... simple bottom line here.... if you don't have significant and similar flow from both exhausts , don't go ANYWHERE. you don't have to roast the motor to know it is going to happen.

second.... im not sure if im reading your first post correctly but if you are saying that it DIDN't do this BEFORE you did the first work and now it does, then it is prettty simple... something was done wrong the first time. the water system is very simple on this motor. no magic at all.... water comes into the pump thru the pickup... make sure it isn't plugged and that the hose that feeds it isn't crimped or collapsing... it should be a wire reinforced hose.... and then touch every part of the cooling system with the same approach...

and pay particular attention to what you changed the first time. thats where the problem will be.

Prostreeter

Appreciate all the advise here.Told the shop today to inspect every part of the cooling system including removing the outdrive to verify blockage or not.The shop feels the thermostat is causing all the water flow and over heating problems.Will take the boat out again and test it this afternoon.

awsomethunder

just for my info how can i check that inlet hose thru the transom.do i remove the drive?gimbal ring?is it a rubber hose and the inside of the drive corrodes and squeezes the hose?

Viper31

As never-satisfied describes, I had the same problem. Check the housing that connects the hose from the sea water pump inlet to the inner transom assembly. They will swell inwards and restrict flow. Follow the sea pump hose back to the transom you will see what I mean. Two bolts hold it on. It looks like a thermostat housing from an early chevy but it is plastic.

Prostreeter

This over heating the starboard manifold is now just ridiculus.The shop went out with me today on the lake after installing the thermostat.They swore this was the problem.Out of the no wake zone,up on plane and bingo the starboard exhaust burnt up again.Temp was 180.They are absolutly confident there is no water restriction anywhere on this engine.

Damn I think I got a faulty IMCO exhaust manifold because I never had this problem with the stock Merc exhaust manifold.Has anyone EVER seen this problem before.I'm going back to the stock exhaust and sure hope IMCO refunds my money.

jayhawk261

As I said Prostreeter, I have seen this EXACT same problem with the Stainless Marine brand manifolds. You have good flow through the port, but not through the starboard. The problem is in the manifold jacket system. Either a fitting is bottomed out, or the manifold was manufactured incorrectly. Before you give up, check those fittings. the problem is in the manifold. I don't see how any of the other issues would block flow only on one side.