Wanderlodge Owners Group  
BuyByeBlueBird.com
WOG YouTube

Go Back   Wanderlodge Owners Group > Mechanic's Corner > Generators

Generators In this forum we will try to answer any of your questions about the different model generators that can be found on Blue Bird coach's.

Site Search:
Reply
 
Thread Tools
  #1  
Old 01-04-2024
brelix brelix is offline
Member
 
Join Date: Jul 2021
Location: Bellingham
Posts: 54
Default Yanmar Maintenance and Hose Replacement

My bird has a 12.5kw Kohler generator with a Yanmar diesel motor (4TN82E-UK). I've had problems with it stalling out and big drops in the output current when it is running. It will charge the batteries fine for a few minutes and then the output current drops significantly and it hardly does anything for my batteries 90% of the time. Then during our last trip, all of the coolant leaked out! Man was I relieved to find that it was just the generator leaking and not the main coolant loop for the engine! It was one of the 35 year-old coolant hoses that runs out to/from the radiator where it had rubbed against the bolt on the hose clamp of the hose next to it. Those two hoses get moved around a lot when the generator tray slides in and out.

When originally troubleshooting the stalling issue, I noticed that either the oil switch or the thermostat switch would kill the fuel solenoid. it would keep running if it I held it open. So I did a bunch of much needed maintenance and replaced some parts before the last trip:
- replaced the thermostat switch
- replaced the oil switch
- replaced the oil pressure sender (OP gauge didn't work)
- changed the engine lube oil & filter
- changed the engine air filter
- changed the secondary fuel filter

It turns out that I missed the primary stage Racor FG-500 fuel filter since it was under the front bumper and not in the generator bay. Aside from all of the coolant leaking out of the generator, the primary fuel filter might have been my main issue. It was so gunked up and blackened that I'm surprised she ran at all! I rebuilt the Racor with a bowl kit and new filter, and I pulled the two fuel hoses and all of the coolant hoses--those 35 year-old coolant hoses are so brittle that the crack in half when you bend them.

This weekend I'm going to be putting all the hoses back in and firing it up to find out if I finally solved the issue or not. For the coolant hoses I went with all silicone (ouch it hurt the bank) except for the 2 long hoses that run out to the radiator and back (~5ft of hose). For those two hoses the shop I went to recommended Novaflex 841 heavy duty oil resistant soft wall exhaust/coolant hose since it was only $75 total. However, I'm concerned about their max temp of +210 deg F. That seems a little low for a coolant hose. In the Yanmar operating manual I see:
- Engine inlet water temp max: 186 F
- Engine outlet water temp max: 196 F

But under "Other Pertinent Information" I see the Thermostat rating for the Yanmar engine:
- Start to open: 157 F
- High water temp switch rating: 230 F
- Thermostat switch on: 225 to 235 F
- Thermostat open: 185 F
- Over temp shutdown: 235 F

If the coolant can get above 210 F, doesn't that mean I should find a better coolant hose for those long runs? Also I did not look in the radiator or pull the whole things to rod it out. Would anyone recommend I do that? I haven't had issues with it overheating so far. I think I remember the generator water temp being very reasonable when I ran it last... maybe around 180 F? Here's the datasheet for the Novaflex 841 (see the last page):
https://www.novaflexgroup.com/produc...st%20Hose4.pdf

I've attached the following photos to help follow along:
1. Kohler/Yanmar Generator with tray extended
2. Racor FG-500 before rebuild
3. Racor FG-500 after rebuild
4. Old fuel hoses in a box
5. Old coolant hoses in a box
6. Diagram of coolant hose system (hoses A and D are the 2 long ones I was talking about).
Attached Thumbnails
Click image for larger version

Name:	20231005_134812.jpg
Views:	102
Size:	203.2 KB
ID:	89325   Click image for larger version

Name:	20231216_153006.jpg
Views:	103
Size:	207.6 KB
ID:	89326   Click image for larger version

Name:	20231217_114712.jpg
Views:	103
Size:	204.5 KB
ID:	89327   Click image for larger version

Name:	20231229_164444.jpg
Views:	95
Size:	201.5 KB
ID:	89328   Click image for larger version

Name:	20231229_164452.jpg
Views:	99
Size:	202.0 KB
ID:	89329   Click image for larger version

Name:	20231229_235100.jpg
Views:	113
Size:	197.4 KB
ID:	89330  
__________________
David Goodman
Bellingham, WA
1986 PT38 8v92ta Silver "Dreadnaught"

Reply With Quote
  #2  
Old 01-04-2024
DirtDigger DirtDigger is offline
Senior Member
 
Join Date: Jul 2017
Location: Louisville, KY/Henryville, IN (exit 19)
Posts: 699
Default

Nice job. And a good diagram showing the hose routing.
__________________
Tim and Nadine Parmenter
Henryville, IN (Louisville, KY area)
1988 WBWL #3907
Serial #79235
8v92 DDEC1
Reply With Quote
  #3  
Old 01-04-2024
mose mose is offline
Senior Member
 
Join Date: Jul 2016
Location: Aloha
Posts: 1,289
Default

Quote:
Originally Posted by brelix View Post
...

However, I'm concerned about their max temp of +210 deg F. That seems a little low for a coolant hose.
...

If the coolant can get above 210 F, doesn't that mean I should find a better coolant hose for those long runs?
The 210F rating is awfully close to 212F. Maybe they just don't approve the hose for steam usage? If so, the pressure in your system would prevent steaming. And the higher temp would not be continuous usage, but limited to overheat events. I personally wouldn't hesitate to use that hose.
__________________
Mose Wahlstrom
Aloha, Oregon
1991 WB40 "Dave"
Reply With Quote
  #4  
Old 01-04-2024
mose mose is offline
Senior Member
 
Join Date: Jul 2016
Location: Aloha
Posts: 1,289
Default

Nitrile is VERY oil resistant. But not quite as high temp as EPDM. That's your tradeoff. Maybe just make sure it's not near exhaust or touching hot areas on the engine block.

I've seen lots of hoses fail from oil contact (they soften and balloon), but I've never seen one melted in normal use.
__________________
Mose Wahlstrom
Aloha, Oregon
1991 WB40 "Dave"
Reply With Quote
  #5  
Old 01-05-2024
brelix brelix is offline
Member
 
Join Date: Jul 2021
Location: Bellingham
Posts: 54
Default

Thanks, Mose! That's very helpful information. Yes, the hose is not rated for steam service but it is rated for 200+psi (WP). It also looks like nitrile has more abrasion resistance than EPDM, and the old one failed from rubbing while the generator tray was moving. Of course I'll have to be sure to route the new hoses out of the way to prevent that from happening--plus I'll use one continuous piece of hose for the radiator return hose (D) and do away with the union at D2/D3 so those hose clamps don't become an issue.

I'll post some more pictures and results when I get finished.

Thanks again!
__________________
David Goodman
Bellingham, WA
1986 PT38 8v92ta Silver "Dreadnaught"

Reply With Quote
  #6  
Old 01-05-2024
Bill Pape's Avatar
Bill Pape Bill Pape is offline
Administrator
 
Join Date: Jan 2008
Location: Commerce
Posts: 14,571
Default

Thanks David and Mose for this thread
__________________
Bill Pape
1988 FC, Silver Edition
Commerce, Michigan
Reply With Quote
  #7  
Old 01-10-2024
brelix brelix is offline
Member
 
Join Date: Jul 2021
Location: Bellingham
Posts: 54
Default An update with new hoses in place

I spent last weekend installing the new coolant hoses. It went okay. The one issue I'm concerned about is a small dent in the top hose (~ 3.5' of 1-1/2" novaflex 841) that runs to the top of the radiator. I circled in red the dent shown in attached images 4 and 5. It isn't a very deep dent, but it does get a bit deeper when the generator tray is all the way in and I'm concerned about this worsening over time (coolant heat and use of the tray in/out feature). That may be why the original hose was more rigid and had steel wire coiled through it.

It's relatively easy to squeeze the bend out by hand. So I wonder if I can use an old radiator hose with some zip ties (like I did for rub protection in image 6) to squeeze it open a little more and prevent it from collapsing at all when the tray is in. Another option would be to cut the hose at the bend and put in a coupler piece--the old hose had a coupler here but that ultimately was the failure point where it rubbed on the other hose before. Again, the dent is relatively minor and the top hose should be higher pressure since it's running to the inlet/top of the radiator. I plan to use a cooling system test/refill kit. I'll check that hose regularly when all is said and done. Is there anything I should keep an eye out for when I finally run it?

Another thing for the wishlist is to pull the whole tray and generator out, repaint it, and redo all of the insulation in the generator bay like I've seen some people do on WOG. That old insulation is messy and crumbly and a bit oily, and the generator door lock sensor system is broken and soaked in grime at the bottom. I think the fabric-covered silicone hoses (lighter blue, 1") shown in image 2 might be more sensitive to oil and dirt smudges. Hopefully they will hold up in there since they cost $71.56 per 3 foot stick.

Next up I plan to do a little more rub protection for the silicone hoses inside the generator bay and add in more zip ties all around. After that I'll put the rebuilt Racor back in with the new fuel hoses and zip tie everything back together (I must have cut 20 zip ties to do all of these hoses!). Then once I put in the new oil pressure sender and oil switch, I'll fire it up and run the whole thing with distilled water for 5 or 10 minutes before I flush and refill with 50/50 of the green stuff. When I get done I'll make a list all of the part numbers and price of everything. The fuel and coolant hoses alone were: $1,137!
Attached Thumbnails
Click image for larger version

Name:	1_20240108_110112.jpg
Views:	94
Size:	204.3 KB
ID:	89425   Click image for larger version

Name:	2_20240108_110129.jpg
Views:	86
Size:	202.2 KB
ID:	89426   Click image for larger version

Name:	3_20240108_110032.jpg
Views:	76
Size:	196.1 KB
ID:	89427   Click image for larger version

Name:	4_20240108_105953_dent2.jpg
Views:	67
Size:	196.5 KB
ID:	89428   Click image for larger version

Name:	5_20240108_105852_dent1.jpg
Views:	73
Size:	197.3 KB
ID:	89429   Click image for larger version

Name:	6_20240108_105723.jpg
Views:	70
Size:	199.6 KB
ID:	89430   Click image for larger version

Name:	7_20240108_105738.jpg
Views:	66
Size:	191.7 KB
ID:	89431   Click image for larger version

Name:	8_20240108_105746.jpg
Views:	74
Size:	190.8 KB
ID:	89432  
__________________
David Goodman
Bellingham, WA
1986 PT38 8v92ta Silver "Dreadnaught"

Reply With Quote
  #8  
Old 01-10-2024
Randy Dupree's Avatar
Randy Dupree Randy Dupree is offline
Forum owner
 
Join Date: Dec 2007
Location: Port St Joe,Fl
Posts: 51,435
Default

Quote:
Originally Posted by brelix View Post
I spent last weekend installing the new coolant hoses. It went okay. The one issue I'm concerned about is a small dent in the top hose (~ 3.5' of 1-1/2" novaflex 841) that runs to the top of the radiator. I circled in red the dent shown in attached images 4 and 5. It isn't a very deep dent, but it does get a bit deeper when the generator tray is all the way in and I'm concerned about this worsening over time (coolant heat and use of the tray in/out feature). That may be why the original hose was more rigid and had steel wire coiled through it.

It's relatively easy to squeeze the bend out by hand. So I wonder if I can use an old radiator hose with some zip ties (like I did for rub protection in image 6) to squeeze it open a little more and prevent it from collapsing at all when the tray is in. Another option would be to cut the hose at the bend and put in a coupler piece--the old hose had a coupler here but that ultimately was the failure point where it rubbed on the other hose before. Again, the dent is relatively minor and the top hose should be higher pressure since it's running to the inlet/top of the radiator. I plan to use a cooling system test/refill kit. I'll check that hose regularly when all is said and done. Is there anything I should keep an eye out for when I finally run it?

Another thing for the wishlist is to pull the whole tray and generator out, repaint it, and redo all of the insulation in the generator bay like I've seen some people do on WOG. That old insulation is messy and crumbly and a bit oily, and the generator door lock sensor system is broken and soaked in grime at the bottom. I think the fabric-covered silicone hoses (lighter blue, 1") shown in image 2 might be more sensitive to oil and dirt smudges. Hopefully they will hold up in there since they cost $71.56 per 3 foot stick.

Next up I plan to do a little more rub protection for the silicone hoses inside the generator bay and add in more zip ties all around. After that I'll put the rebuilt Racor back in with the new fuel hoses and zip tie everything back together (I must have cut 20 zip ties to do all of these hoses!). Then once I put in the new oil pressure sender and oil switch, I'll fire it up and run the whole thing with distilled water for 5 or 10 minutes before I flush and refill with 50/50 of the green stuff. When I get done I'll make a list all of the part numbers and price of everything. The fuel and coolant hoses alone were: $1,137!
You did use the wog discount at siliconhose.come,right?
we set up a darn good discount program with them,hope you used it.
__________________
DO NOT SEND PM
email me at randy@randydupree.com only.

Randy Dupree
2000 LXI 43
Bainbridge,Ga.
Port St Joe Fl.
www.buybyebluebird.com

randy@randydupree.com
Reply With Quote
  #9  
Old 01-10-2024
Justdoingit Justdoingit is offline
JustDoingIt
 
Join Date: Jun 2017
Location: Chiefland
Posts: 69
Default

I have these type of hose protections everywhere on the bus where something might rug against hoses. They have the ridges to hold zip ties in place, and made of heavy material.

Click image for larger version

Name:	IMG_1475.jpg
Views:	86
Size:	96.0 KB
ID:	89434
__________________
Jeff Barfett
1987 PT36
Reply With Quote
  #10  
Old 01-10-2024
wandermore wandermore is offline
Super Moderator
 
Join Date: Jan 2021
Location: Winchester
Posts: 1,793
Default

Nice work! That kink would make me a little nervous too. I would probably address it since I learned recently how much my family hates it when the generator runs unreliably on a trip.

If it were me, I would probably replace the coupler there and then wrap it with one those protectors Jeff posted or just a piece cut from a larger hose I had sitting around fastened with stainless zipties or hose clamps.
__________________
Jim Reynolds
Winchester, Tennessee
'99 LXi
Reply With Quote
Reply

Bookmarks

Tags
coolant hoses, fuel filter 12.5 gen, generator problem, yanmar

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Yanmar maintenance NH Bill Generators 15 08-09-2023 09:13 PM
Hydrolic Hose Replacement rgus General 6 02-13-2023 10:01 AM
Yanmar/Kohler Coolant Hose ICBM99 Generators 73 08-27-2017 01:53 PM
Compressor Hose Replacement Guest5203 General 7 01-06-2016 08:26 AM
Stratoflex hose replacement Harrison Engine 0 02-23-2012 05:07 PM

Web Search:

All times are GMT -4. The time now is 06:11 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.