Joker460: Turning 2GM20F CW Pump around

[Ken13559]

Hello Joker460, I've been reading your post on the modification to turn the CW Pump around using the 3YM30 pump bracket. I've the parts required for this job but unsure what size V-belt you finally used. Could you advise, should it be 3L180 (18"OD) or 3L170 (17"OD)? Thank you.

Ken

 

[joker460]

The one I used on my installation was the 3L-180.

It's interesting that you can do it on the 2GM20F. There have been some others that have made the modification with good results, I hope At least they haven't yelled at me.

 

[Ken13559]

Joker460, thank you. I'll pick up the belt from shop shortly. It'll be awhile before i assemble everything.
The pump pulley seems pretty close to the crank pulley guess I'll know when done. I suppose yoou bought the 3" diameter Speed Seal Life cover. I asked Speed Seal for model to buy and was told to measure the pump cover diameter.
Thanks again.

 

[joker460]

That's strange. I got it from here http://www.speedseal.com/SpeedsealLife/Lifeusaprices.htm

All I told them was it was a Yanmar 3G30Mf and they sent the correct cover.

The belt size I selected was to keep clear of the motor mounts base. Your setup might be slightly different depending where your base is in relation to the pump. You don't want the pump frame too close to the base as it will hit when the motor is started.

I originally had ordered the 19, 18 and 17 inch belts. The 19" let the pump frame touch the base which was not good. I could have used the 17" but that would have brought the pump pulley A bit too close to the main pulley.

 

[DougM]

Joker460, thank you. I'll pick up the belt from shop shortly. It'll be awhile before i assemble everything.
The pump pulley seems pretty close to the crank pulley guess I'll know when done. I suppose yoou bought the 3" diameter Speed Seal Life cover. I asked Speed Seal for model to buy and was told to measure the pump cover diameter.
Thanks again.

Be careful when you order the speed seal cover. Yanmar used two different pumps on the 2GM20F. The Euro built engine used a Johnson brand pump which already has an O-ring seal in the cover where the Asian version uses a pump with a gasket seal (not sure of the brand).

 

[Ken13559]

Joker460, your motor base look like mine.
Doug, thanks for the info. Perhaps that's why Speed Seal asked for my pump cover diameter. My pump look just like Joker460's photo above.
Will get the pump mod working good before ordering Speed Seal.
Can't wait to get started.

 

[DougM]

The one I used on my installation was the 3L-180.

It's interesting that you can do it on the 2GM20F. There have been some others that have made the modification with good results, I hope At least they haven't yelled at me.

Did anyone ever get a definitive answer as to whether the fact that the pump will be rotating in the opposite direction makes a difference?

 

[woodster]

Did anyone ever get a definitive answer as to whether the fact that the pump will be rotating in the opposite direction makes a difference?

yes it makes no difference ...i ate some crow over that one

 

[pateco]

I am wondering if this could also be done on the older 2GM. Looks like I have the space in front of the engine.

This really looks like it would simplify impeller maintenance. Stupid question. How often do you check/change your raw water impeller? This is all new to me, and want to make sure I take good care of my new baby. I know I have two spare impellers, and an entire spare pump in the parts left by the PO.

Also, since mine is raw water cooled. I am toying with the idea of adding a fresh water flush so that I can flush the engine after each use. Has anyone done this, and what should I look for / watch out for?

 

[Ken13559]

I tried the modification with 18" v belt. The crankshaft pulley is scraping the cw pump pulley. I switched back to the original 19" v belt. Pulleys not touching but unable to tighten v belt as adjustment slot is at the end. Need it to be a little longer. I'll need to fabricate a new slotted plate, fashion against existing one but with longer slot length.

 

[joker460]

Did you take any pictures that you can upload with the 18" belt.
I wonder if there's a slight difference between the 3GM30 and 2GM20 in center spacing.
What is the clearance (face to face) between the pump sheave and the crank sheave?
Maybe a shim between pump and bracket to give more clearance?
You did put the washer between the pump shaft and pump sheave?

Did a little further looking. It seems the front end of the 2GM and 3GM are the same length but the clearance between the two sheaves looks to be different.
There seems to be more clearance on the 3GM. The drawings are attached.

 

[Ken13559]

Sharks! I didn't take any pictures.
When fitted, the clearance between the pump & crank sheave range from 0-1mm when I turned the crank sheave. It did not occur to me to add more washer behind the pump sheave. That would certainly add 1-1.5mm more clearance.
Ok I'll have to try this mod again. Think I'm getting good at dismantling and fitting it up now after ssooo many tries.
I'll try to remember to take pictures next attempt.

 

[joker460]

The silence is deafening. Did you manage to get it working??? :neutral: