Yamaha - excessive smoke

[dhawk]

'87 Yamaha 225hp Excel. Oil consumption gradually increasing. Now very high, aprox. 30:1. At the end of the last trip, the engine was smoking at idle like it was on fire. I assume the oil pump is not metering properly. Is there a check valve of some sort that has failed allowing for excessive oil. If it is the pump, can it be fixed or must it be replaced? Thanks

 

[ICEMAN]

Re: Yamaha - excessive smoke

check the rod from the oil pump to the throttle linkage. if it fell off the oil pump will go to max oil delivery

 

[dhawk]

Re: Yamaha - excessive smoke

It's ok. Still connected.

 

[BruceAML]

Re: Yamaha - excessive smoke

Go to the yamaha-motors web site and look up the parts diagram in the OIL PUMP section and also in the OIL PUMP CONVERSION section. The original oil pump has the check valves built into the oil pump and the replacement or conversion kit has separate check valves. If your pump has not been converted it would be good to do it. What kind of oil are you using?

 

[dhawk]

Re: Yamaha - excessive smoke

Thank for the reply Bruce.

I don't know which pump I have. Is the only difference between them the check valves? If the check valves prevent oil from flowing back to the pump, how does this affect the amount of oil going to the manifold?

I've been using West's TCW III. I've used it in my the motor I had before this, an 86 200 yamaha with no problems so I continued to use it.

 

[BruceAML]

Re: Yamaha - excessive smoke

I believe the original pump is a Keim pump and the replacement is a Mikuni pump. If you do not have external check valves, than you have the original pump. If you give me the exact model number I can tell you the replacement pump number. If you have a Yamaha manual you can measure the amount of oil that is pumped into the engine. This test must be done using oil and gas mixture in the fuel tank. Print out the pictures from the parts list as they will be much larger and you can easily determine which pump you have. How are your spark plugs and carburetors?

 

[dhawk]

Re: Yamaha - excessive smoke

I checked the website. One pump is labeled "replacement" the other is labeled "oil pump kit". They have 2 different P/Ns. I'll try and get to it today to give you the info on mine. Thanks.

 

[dhawk]

Re: Yamaha - excessive smoke

Bruce: You are right about the pumps. I have the old style marked on the side
"KEIHIM". Didn't have to remove the pump. Name is visible. The replacement p/n for pump from the Yam. web site is 6R13200-09-00. Do I have to get check valves too?

Why would I have to test oil output. Don't I already know that too much oil is getting into the cylinders?

Regarding plugs, they are fouled with oil.

I'm not going to touch the carbs at this point.

 

[Ray Neudecker]

Re: Yamaha - excessive smoke

Measure the output to prove that is the problem. On that model the more likely culprit is a malfunctioning engine mounted tank sensor or shorted oil control module over filling the tank and being dumped into the air box.

 

[dhawk]

Re: Yamaha - excessive smoke

I think I'm starting to understand. Oil could be forced through the skinny vent tubing on the top of the tank into the air box a then sucked into the carbs?
If in means anything, the oil level in the motor tank is exactly at the uppermost fill mark. At the risk of being a pest, why can't I just disconnect this hose from the air box and see if oil is comes through from the tank? I had this problem on an 86 200 and the tank sensor kept popping out of the tank.

Thanks for your patience, Ray

 

[BruceAML]

Re: Yamaha - excessive smoke

You definitely have the original pump so you would need to order the replacement kit which contains the check valves and all of the necessary parts to convert to the new style pump. I like the Mikuni pump better and so does Yamaha. Having said that, an oil pump output test is the first step in determining the problem.

 

[Ray Neudecker]

Re: Yamaha - excessive smoke

Not sure why you prefer the Mikuni pump system better. The Keim pump has certainly stood the test of time. I have seen more failures with the newer system than the old since they changed the original gear in the first motors.
Even though many of the problems with the newer have been due to clogged valves from the use of lower grade oils.
Yes you can disconnect the hose from the air box and see if the excess oil is ending up in the cowling instead of the air box.

 

[dhawk]

Re: Yamaha - excessive smoke

Thanks again for your help. Will try and look at it today.

 

[dhawk]

Re: Yamaha - excessive smoke

Checked pump output. At 1500rmp, 3 minutes, pump open, all lines discharge aprox. 1cc. Disconnected pump & found some oil behind the pump where it bolts on the block. Is there supposed to be oil behind the pump? The seal was wet, but it looked ok. Also, there is what appears to be a small hole in the bottom of the mounting area. Could oil be draining through this hole into the cylinders?

 

[BruceAML]

Re: Yamaha - excessive smoke

When you do the oil test it is important that the fuel tank have an oil/gas mix (50:1) and not use straight gas. 1cc seems low. Did you look in the manual to see the amount that should be pumped. You also need a graduated container to precisely measure the amount of oil pumped.

 

[dhawk]

Re: Yamaha - excessive smoke

I did run on separate 50:1 mix. and used a graduated 10cc container to measure oil. The specs come from 2 manuals. One is an '86 shop manual for a 200hp which has the same pump. It states: "each port must emit a minimum of 1cc in three minutes". However, a spec sheet on the same page lists oil discharge for 3 minutes as 2.6cc minimum and 4.0cc maximum. More confusing, it has a drawing showing 2 containers with both quantities.
The other is a Clymer manual and lists 0.76cc for all motors 25-300hp and 2.6-4.0cc for 115-225hp. More confusing info. Since I was meeting at least one spec (1cc) and all lines discharged the same amount and since my problem is over oiling, as opposed to not enough, I was satisfied with the results. That's why I asked about oil behind the pump. It would seem to me that excess oil has to be getting into the engine somehow. I realize this is a lot of info to digest, but I really do appreciate the help.

 

[dhawk]

Re: Yamaha - excessive smoke

BTW the vent hose from the motor tank is dry. To double check, I drained the motor tank. The boat tank pumped oil and stop filling when the oil reached the top fill mark. There is no residual oil in the air box. So it appears that it is not a problem.

 

[drewmitch44]

Re: Yamaha - excessive smoke

When you run the oil delivery test you have to make sure to unhook the linkage to the oil pump so that the oil pump opens up all the way to the max delivery rate. Then you should get the 2.6-4.0 cc's. The easiest way to measure i found was a syringe that measures cc's or ml's which is the same thing. I did the test and with the linkage hooked up i got about 1 cc in the 3 min. and @ 1500 rpm. I was thinking that it was supposed to be to the 2.6-4.0 cc's. I called the shop and the 1cc is for when you leave the linkage hooked up as normal and the 2.6-4.0cc's was when you open up the pumb by disconnection the linkage. I dont know if this helps you or not. When i was testing mine out i was so confused as to what to do. I couldent figure out the numbers i was supposed to be getting till i called yamaha. I was also told that you have to bleed out the lines each time you do the test and the guy told me to run on the mixed gas for a little bit to make sure all the air in the lines gets worked out before you switch back to strait gas. Im not an expert of any kind on this i just had the same confusion as you are having.

 

[drewmitch44]

Re: Yamaha - excessive smoke

ohh the syringe with the needle twisted off of it the oil tube pluged right into the bottom of the syringe. It was like it was ment to be if ya know what i mean. Its hard to measure such a small ammount of liquid if you use a container. Also the oil sticks to the sides if you pour from one container to another. This is why used the syringe. When i called yamaha thats what they sudjested for propper measurement. The one i used went up to 10 ml's. I got the propper delivery rate so i did not replace my pump but i was wondering how you determine which one you have installed. I still am not sure but since its working ok im not going to mess with it.

 

[dhawk]

Re: Yamaha - excessive smoke

drewmitch: I used a syringe too, but pulled the needle, covered the hole and filled it from the top. I disconnected the rod and opened the pump lever all the way when I ran the test. I didn't clear any lines. I just pulled each line, check the flow, reconnected it and moved on to the next one all while the 50:1 mix was hooked up. The pump is marked on the side. Mine says KEIHIM.