89 225 Yamaha V6 Excel Overheating

[Key Largo]

1989 225 Yamaha V6 Excel was running great until the water impeller went out. I replaced the impeller, housing, and everything else that came with the kit. Also replaced both thermostats. Now it pumps water at idle, but as the engine heats up, it stops pumping water and eventually overheats in about 5 minutes. Any ideas ?

 

[rodbolt]

Re: 89 225 Yamaha V6 Excel Overheating

remove and clean the water pressure valve. remove the gromet carefully clean all the corrosion from the pocket and install a new grommet. most likly even when its pumping you have low water pressure. sometimes they stick open some and cant fill the block with water. common problem on low maint motors.

 

[Key Largo]

Re: 89 225 Yamaha V6 Excel Overheating

I really appreciate the advice. Where is this valve located ?

 

[rodbolt]

Re: 89 225 Yamaha V6 Excel Overheating

look on the exhaust cover just below the coils. if the screws are corroded in use oxy/acetylene to remove them. if you break them its a pain. the cover looks like a t-stat housing with 2 10mm hex bolts and a large rubber hose.

 

[seahorse5]

Re: 89 225 Yamaha V6 Excel Overheating

When the impeller "went out", did the rubber vanes break off and go up the water tube into the motor?<br /><br />If so, that could be part of the problem.

 

[Key Largo]

Re: 89 225 Yamaha V6 Excel Overheating

Thanks for the advice. Long story short. turns out that there is overheating damage and I will be rebuilding the engine.

 

[rodbolt]

Re: 89 225 Yamaha V6 Excel Overheating

if you need any parts,other than a block, I may have some.

 

[Ray Neudecker]

Re: 89 225 Yamaha V6 Excel Overheating

Unlikely to need a block if motor will still run, but I have a number of them if needed.

 

[Key Largo]

Re: 89 225 Yamaha V6 Excel Overheating

I appreciate that and will keep in mind during the rebuild. Motor won't run. I plan on making some upgrades along the way too. ie.e valves in the oil lines, fresh water adapter for flushing.

 

[rodbolt]

Re: 89 225 Yamaha V6 Excel Overheating

hello<br /> if you have the old style oil pump with the nipples all pointing up look into the pump kit upgrade. the mikuni pump was a much better pump. the adding oil line check valves on the old kien pump was a temporary patch.

 

[rodbolt]

Re: 89 225 Yamaha V6 Excel Overheating

ray<br /> you got any decent freshwater 89 225 blocks ?

 

[Ray Neudecker]

Re: 89 225 Yamaha V6 Excel Overheating

I will have to look and see. I usually rathole them for the racers. The 87-89 models were the bad boys. I know I have some later models or can bring most of the blocks up to those specs. I recently found what is supposed to be some, but haven't gone and checked them yet. Note that the V-6 Special was the exact same block with a vertical front half. If you are just looking for a fresh block with the same HP or better, no problem.<br /> I have recently agreed to do some blocks and set ups for a team planning to circle race the Formula 150 class and depending on the rules interpetation will determine if I can update or blue print other blocks or have to run these.<br /> It appears the Mercury people have thankfully got a blueprint rule through that may turn around and bite them.<br /> Are you sure you can remember how to work on something without a torch?<br /> Drop me an email at neudecray@hotmail.com and I will reply in a very few days. Should have all info together the first part of next week.

 

[rodbolt]

Re: 89 225 Yamaha V6 Excel Overheating

yea Ill shoot ya a mail soon.<br /> I have a very nice 225 excell that is an 89 sold new in 95 and while testing for a plug fouling complaint, found some bad recirc check valves, I saw water pouring from the steering tiller. removed the powerhead and found a hole corroded through the water cross over passage under the block just aft of the V. whole thing had less than 250 hours. I ended up with it complete from controls to prop. used the gearcase and midsection on another project but now I have a complete 93 200 with less than 200 hours with a hole in the block.

 

[Ray Neudecker]

Re: 89 225 Yamaha V6 Excel Overheating

The 93 200, I should have in a standard bore ready to put together. Is it vertical or horizantal?

 

[rodbolt]

Re: 89 225 Yamaha V6 Excel Overheating

dont know about the 200. have not opened it up nor looked closly at the intake. it was purchased by a Dr from the great lakes area and run 3 weekends here in 4 years. I mounted an F225 and in 3 years he has put 41 hours or so on it. the 200 is clean as a new one.<br /> Ill check and get back. for the 200 it will need a crank and a block. the 89 225 purred like a kitten just leaked water.