yamaha stern drive over heat

[bmack4life]

ok, i have a yamaha i/o 5.0L (305 gm) just picked it up from the dealer, went out and ran her for about 20 min, when i brought it down i lost oil pres and got a buzzer, checked oil, all was sat, running between 140 and 160 on water temp. while traveling at clutch ahead to the trailer the alarm cleared and oil press jumped up. when i ran it at the shop (right after this trip) i got the buzzer again but good oil press, at this time the temp hit 240 very quick and had no water discharge. i assume the therm. or pump went, but it doesnt add up to me..i ran it on the ears before this trip but for a short time, can this engine be cooled properly with the ears??

 

[Don S]

Re: yamaha stern drive over heat

Doesn't matter the year, make, model or anything else. The first thing you check when you have any kind of over heat problem is the raw water pump impeller.

On the muffs (ears) or in the water under load it two completely different methods of testing. On muffs, with no load and hose presure keeps thing cool.
Under load always creates more heat, without the hose pressure.

 

[Bondo]

Re: yamaha stern drive over heat

ok, i have a yamaha i/o 5.0L (305 gm) just picked it up from the dealer,

Ayuh,...... Bring it Back.........

Dd you Just buy it,.... Or was it already Your's,+ it was being serviced,..??

 

[Capt Ken]

Re: yamaha stern drive over heat

First off, with the Yamaha you need a good set of muffs. I use the Bravo type with the pin that goes thru the intake. Crank the water pressure to it before firing up the engine. Due to the age of the system, the water pump is probably worn and it don't have the sucking power it use to. You probably fried the impeller so its time to pull the pump off and inspect.

 

[Don S]

Re: yamaha stern drive over heat

So, Capt Ken, where is the raw water pump on a Yamaha Outdrive setup like his?

 

[Capt Ken]

Re: yamaha stern drive over heat

Remove engine cover. Face engine. Take your right hand and touch the lower pully on that side of the engine. You are now touching the water pump. Align the two holes in the pully with the two 5/16 bolts hidden behind it. Using a 1/2 inch socket on a 3/8 drive with a six inch extension, remove the two bolts. Pump will then drop. Remove two hoses and presto chango, the pump is now free from the engine. Remove three 1/4 bolts from rear of pump and the impeller will be visable.

 

[Don S]

Re: yamaha stern drive over heat

Thanks Ken, I was mostly wondering if was an engine mounted or in the outdrive like OMC and Mercs.

 

[Capt Ken]

Re: yamaha stern drive over heat

Very simple Sherwood pump. Now the 3.0 uses a oriental pump that is near impossible to find parts for.

 

[bmack4life]

Re: yamaha stern drive over heat

thanks guys, i think its a def prob with the ears, just before i ran it on the ears i was u/w for 30 min at full, she ran at 160? the whole time. i had a bad oil sensor and set the alarm off just before coming in, i ran it on land with the hose to test the alarm and got it again thinking it was oil, but it reached 200? and i had no water discharge. at the time i thought the oil sensor was never bad and the alarm was the temp the whole time, but cant be, she ran like a top even after the alarm cleared. i've been busy the past week with other peoples head aches! but i'm gonna take it to the ramp and run it to see what is going on, i'll keep you updated. i do have one more question... i'm thinking about changing up a few things, one: i have a thru hull on the center line just forward of the engine for the old raw water washdown, i want to convert that to the r/w suction for cooling and add a strainer. (gonna use a speed thru hull fitting) can i bypass the cooling from the lower unit? and i have been thinking about adding a heat exchanger to use jacket water rather than salt water to the engine, i have the resources to do all this and the skill, does this seem like a good idea, or just a wast of time? thanks again guys, oh and by the way the run i did on it was a sea trial at the dealer and this issue got me the boat for $1500, considering the shape of the boat and trailer i just took the deal! i'm considering filling the hole and putting 2 outboards on a bracket if all else fails!!