Reply
 
Thread Tools Search this Thread Display Modes
 
Old 10-28-2021, 02:54 AM   #1
Member
 
Randomwake's Avatar
 
City: Campbell river
Vessel Name: Random wake
Vessel Model: 76í CHB 34í tricabin
Join Date: Oct 2021
Posts: 5
FL 120 temperature

Just bought a 34chb trawler And have two questions :
1- Manual says optimum engine operating temp is 190, but it only gets to 150. Not sure if anyone else has encountered this? I assume I just need a different thermostat but not sure if it is deliberately set lower? Possibly to keep #6 cool as Iíve heard there can be some issues.

2- Iím trying to troll with this big brute, at high idle to
Ensure good combustion, if Iím at 900-1000rpm I should be getting good combustion eh? Donít want any engine damage, if Iím not getting great combustion what is the harm? Just fuel dilution in the oil? Or something more?

3- it trolls too fast so Iíll be kicking it in and out of N a lot. It shifts incredibly smooth! Is this bad for the transmission or is it no diffeRent than pressing the clutch in your car?
Randomwake is offline   Reply With Quote
Old 10-28-2021, 04:27 AM   #2
Veteran Member
 
City: Baltimore, Maryland
Vessel Name: HAVEN
Vessel Model: Golden Star 35
Join Date: Jul 2013
Posts: 88
Hello Random, are you just using your gauges? Try a laser or infrared thermometer for comparison. Then check your thermostat, if there is one.
artfulltune is offline   Reply With Quote
Old 10-28-2021, 07:05 AM   #3
Guru
 
catalinajack's Avatar
 
City: Edgewater, MD
Vessel Name: Catalina Jack
Vessel Model: Defever 44
Join Date: Nov 2011
Posts: 2,835
Quote:
Originally Posted by Randomwake View Post
Just bought a 34chb trawler And have two questions :

1- Manual says optimum engine operating temp is 190, but it only gets to 150. Not sure if anyone else has encountered this? I assume I just need a different thermostat but not sure if it is deliberately set lower? Possibly to keep #6 cool as Iíve heard there can be some issues.



2- Iím trying to troll with this big brute, at high idle to

Ensure good combustion, if Iím at 900-1000rpm I should be getting good combustion eh? Donít want any engine damage, if Iím not getting great combustion what is the harm? Just fuel dilution in the oil? Or something more?



3- it trolls too fast so Iíll be kicking it in and out of N a lot. It shifts incredibly smooth! Is this bad for the transmission or is it no diffeRent than pressing the clutch in your car?
After confirming the temp with an infrared thermometer, if your operating temp is, in fact, 150 degrees you should consider changing your thermostat to a 180-degree model. My FL120s, with 180 thermostats run at 182 degrees as measured by a high-quality Fluke IR thermometer. Running too cold, over time, risks fuel dilution of your lube oil. I found this out (oil analysis) by using 160-degree thermostats for a time, a poor decision.
catalinajack is offline   Reply With Quote
Old 10-28-2021, 07:55 AM   #4
Valued Technical Contributor
 
DavidM's Avatar
 
City: Litchfield, Ct
Join Date: Aug 2012
Posts: 6,092
Your thermostat may be stuck in the open position. A quick test to confirm is to run the engine at wot for 5 minutes after it is warmed up to 150. If it quickly rises 20-30 degrees, it is likely stuck open.

David
DavidM is offline   Reply With Quote
Old 10-28-2021, 09:23 AM   #5
Senior Member
 
Tator's Avatar
 
City: Bainbridge Island/Petersburg Alaska
Vessel Name: Oz
Vessel Model: Bluewater 40' RPH 1979
Join Date: Feb 2015
Posts: 385
I'm sure it can be a bit harder on the transmission to keep shifting it in and out. That being said, we too troll by shifting our B-W trannies and have been doing it for 15 years. We also spent many years and hundreds of hours shifting them in and and out while researching and recording humpback whales. Keeping your rpms below 850 and shifting slowly will help. It's the flex plate that will go. We also have flexible couplings on our shafts that help absorb the shock. Of course...they could go out tomorrow. And be sure and run your engine at 180deg and run it hard for a few minutes after running it at trolling speeds.

Tator
Tator is offline   Reply With Quote
Old 10-28-2021, 09:52 AM   #6
Guru
 
Soo-Valley's Avatar
 
City: Gulf Islands, BC Canada
Vessel Name: Soo Valley
Vessel Model: Grand Banks 36
Join Date: Jul 2019
Posts: 2,005
Stop shifting to obtain troll speed. Why high idle, what is wrong with just idle.
Check the thermostat. If it is rated 180 and running 150 it could have had a hole drilled to prevent air getting trapped. At idle that is enough flow to keep temp lower.
__________________
SteveK AKA Soo Valley
You only need one working engine. That is why I have two.
Soo-Valley is offline   Reply With Quote
Old 10-28-2021, 11:30 AM   #7
Guru
 
Cigatoo's Avatar
 
City: Narragansett Bay
Vessel Model: Grand Banks 36
Join Date: Sep 2016
Posts: 1,335
I think that the "earlier" Lehmans came with 150 degree thermostats. They were later changed to higher temps such as 190. You can email American Diesel with your questions / parts requests. It would be helpful to have the engine serial number included in the email.
__________________
Charlie0
Cigatoo is offline   Reply With Quote
Old 10-28-2021, 12:56 PM   #8
Guru
 
Marco Flamingo's Avatar
 
City: Dewatto
Vessel Name: CHiTON
Vessel Model: Tung Hwa Clipper 30
Join Date: Jan 2020
Posts: 562
My thermostat had a hole drilled in it and wouldn't heat properly at anything below about 1,800 rpm. There were lots of places where pole holders had been attached on my boat, so I know that the boat was used for trolling and would not have heated properly with a hole drilled in the thermostat. Also, one of the prior owners had installed the heavier Lehman flywheel (100# instead of 87#) to smooth out the idle when trolling. Usually used on the 120 Lehman, I've got one on my 80hp. Smooth idle but probably takes a couple extra seconds to spin up to start.

Stant makes a 180 degree Ford thermostat (PN 45358) that has a "micro channel" that doesn't trap bubbles. No need to buy a "Lehman" specific thermostat. It's a Ford. For $10, you might as well buy one and install it if you're even thinking of looking at your old one. When I took my old one out I saw that it was a 170 with a hole drilled in it, so not even worth keeping as a spare. Stant (and others) also makes a 190 degree for Ford, but I thought I'd split the difference.
__________________
Marco Flamingo
Marco Flamingo is offline   Reply With Quote
Old 10-29-2021, 06:57 AM   #9
Guru
 
catalinajack's Avatar
 
City: Edgewater, MD
Vessel Name: Catalina Jack
Vessel Model: Defever 44
Join Date: Nov 2011
Posts: 2,835
Quote:
Originally Posted by Tator View Post
I'm sure it can be a bit harder on the transmission to keep shifting it in and out. That being said, we too troll by shifting our B-W trannies and have been doing it for 15 years. We also spent many years and hundreds of hours shifting them in and and out while researching and recording humpback whales. Keeping your rpms below 850 and shifting slowly will help. It's the flex plate that will go. We also have flexible couplings on our shafts that help absorb the shock. Of course...they could go out tomorrow. And be sure and run your engine at 180deg and run it hard for a few minutes after running it at trolling speeds.



Tator
Tator, those flexible couplings are not flexible. They do not absorb shock. They fracture when their torque rating is exceeded.
catalinajack is offline   Reply With Quote
Old 10-29-2021, 07:00 AM   #10
Guru
 
catalinajack's Avatar
 
City: Edgewater, MD
Vessel Name: Catalina Jack
Vessel Model: Defever 44
Join Date: Nov 2011
Posts: 2,835
Quote:
Originally Posted by Marco Flamingo View Post
My thermostat had a hole drilled in it and wouldn't heat properly at anything below about 1,800 rpm. There were lots of places where pole holders had been attached on my boat, so I know that the boat was used for trolling and would not have heated properly with a hole drilled in the thermostat. Also, one of the prior owners had installed the heavier Lehman flywheel (100# instead of 87#) to smooth out the idle when trolling. Usually used on the 120 Lehman, I've got one on my 80hp. Smooth idle but probably takes a couple extra seconds to spin up to start.

Stant makes a 180 degree Ford thermostat (PN 45358) that has a "micro channel" that doesn't trap bubbles. No need to buy a "Lehman" specific thermostat. It's a Ford. For $10, you might as well buy one and install it if you're even thinking of looking at your old one. When I took my old one out I saw that it was a 170 with a hole drilled in it, so not even worth keeping as a spare. Stant (and others) also makes a 190 degree for Ford, but I thought I'd split the difference.
Marco, my 180-degree stats have holes and the boat warms quickly to 182 degrees and stays there even at less than 1,600 RPM.
catalinajack is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 05:50 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012