2005 Generac GTV-760 Oil Pressure Problem

bijiminy

Active Member
Joined
Aug 17, 2020
Threads
11
Messages
50
the oil has to float the bearing
What decides if it can do this is, the size of the oil hole feeding the bearing, the pressure that the oil is under , the space between the journal & the bush , the viscosity of the oil.
The first 3 are manufacturing fundamental of the particular engine
I've been thinking about this: If 15w40 oil were recommended, wouldn't straight 30w be okay? It seems in colder ambient temps the thickness of the oil would be on the 40w end and at hotter ambient temps the oil would be at the 15w end. I know it should be just the opposite, because of the additives, but I used to run 15w40 year round in my diesel Ford. It was extremely hard to start in cold weather unless I had the block heater plugged in. When I changed to year round 10w30 diesel oil on Ford recommendation, it was much easier to start. 15w40 would sort of be on a sliding scale so to speak. It has to go through the oil hole feeding the bearing, and this oil would be 30w at some point. Feeding the bearing is the whole issue. Most people only use their lawn equipment from early spring, when it relatively cool but not cold to late summer when it very hot. So, to me, straight 30w makes sense or is my reasoning way off?
 

bertsmobile1

Lawn Royalty
Joined
Nov 29, 2014
Threads
65
Messages
24,995
Now I'm confused. I was going to go with 30w, but now maybe I should go with factory recommendation. I'm pretty sure I have a bad oil pressure switch. Cleaned the contacts. Idiot light still flashing. I think if I had real problems with the engine, it would have stopped by now. Keeps on purring. I have real respect for these old Generacs as long as they are taken care of. I don't want to use synthetic after using conventional. Had a bad experience in the past.
No n
Now I'm confused. I was going to go with 30w, but now maybe I should go with factory recommendation. I'm pretty sure I have a bad oil pressure switch. Cleaned the contacts. Idiot light still flashing. I think if I had real problems with the engine, it would have stopped by now. Keeps on purring. I have real respect for these old Generacs as long as they are taken care of. I don't want to use synthetic after using conventional. Had a bad experience in the past.
No need for confusion.
The owners handbook came with a chart of what viscosity oil to use over certain temperature ranges for YOUR engine.
Ignore all the others because they are not for YOUR engine in YOUR mower .
 

bijiminy

Active Member
Joined
Aug 17, 2020
Threads
11
Messages
50
Thanks everyone for the input. Now I know what I am going to do with the oil. I have one more question. Does the new pressure switch need a thread sealant? Possibly loctite? If so, which color loctite? Or would thread deal tape do or thread putty? What do you all use? Thanks again. The forum is always a lot of help with my stupid questions
 

Scrubcadet10

Moderator
Staff member
Joined
Sep 24, 2017
Threads
267
Messages
6,641
I've always used standard PTFE tape...
 

Joed756

Well-Known Member
Joined
Aug 16, 2013
Threads
2
Messages
221
Does this oil light flash all the time? I'm thinking of the extreme heat we're having, if the light only flashes when you are on a hill or other grade it might just be the oil is hotter (thinner) than usual, so it runs to the sides of the engine and off of the pressure switch.
 

bijiminy

Active Member
Joined
Aug 17, 2020
Threads
11
Messages
50
Does this oil light flash all the time? I'm thinking of the extreme heat we're having, if the light only flashes when you are on a hill or other grade it might just be the oil is hotter (thinner) than usual, so it runs to the sides of the engine and off of the pressure switch.
It flashes all the time
 

hlw49

Lawn Addict
Joined
Jul 11, 2021
Threads
43
Messages
1,607
What model D/C do you have that has an oil light on it. Never seen one most of them have a low oil horn. You are missing the point of the oil, diesels and small engines run hotter that standard gas engines. Most of them have solid lifters except the Kohler command engine which have hydraulic. The Lucas and Rotella oils are designed to run at the higher operating temps of these engines they also have more zinc in them to help lubricate the valve train. The auto industry dropped out most of the zinc because the catalytic convers stop up quicker with the zinc. Lucas is the slickest oil I have ever seen I would stay with it. The dealer you are talking to needs to study up on the oils. Don't run auto oil in small engines it doesn't stand up to the heat and the small engines and diesels like the extra zinc.
 

bijiminy

Active Member
Joined
Aug 17, 2020
Threads
11
Messages
50
What model D/C do you have that has an oil light on it. Never seen one most of them have a low oil horn. You are missing the point of the oil, diesels and small engines run hotter that standard gas engines. Most of them have solid lifters except the Kohler command engine which have hydraulic. The Lucas and Rotella oils are designed to run at the higher operating temps of these engines they also have more zinc in them to help lubricate the valve train. The auto industry dropped out most of the zinc because the catalytic convers stop up quicker with the zinc. Lucas is the slickest oil I have ever seen I would stay with it. The dealer you are talking to needs to study up on the oils. Don't run auto oil in small engines it doesn't stand up to the heat and the small engines and diesels like the extra zinc.
I had an LT2700 Silver Eagle. I believe from the serial number it was from 2005. It had a warning light that flashed and an LED that read check engine oil or something thereabouts. It had no horn. I said "had", because I thought I had a bad oil pressure sender switch and tried to replace it with another. Generac had superseded the old switch with a new one that really didn't fit and I broke the oil sump putting it in, which actually meant I broke the whole engine case, as the sump is not a separate part. I gave the mower to a kid in the neighborhood that has a business. He's going to try and find a Kawasaki that fits. I was putting in the Lucas oil when all this happened. As it turns out, it appears I had good oil pressure all along. Just the wrong oil. I'm now looking at a used 2019 John Deere z960m with 86 hours on it. However, I have not had much luck with zero turns and aluminum block engines. I'm really "gunshy" now. I may just give in and have someone else mow my lawn, which I hate. They never cut it the way I would. I really liked that Dixie Chopper. It was fast and I think the Generac engine was good, but I had no local support. The local Dixie Chopper dealer was no help. He actually said that he had never heard of a Generac engine being used in a Dixie Chopper though he was the one that put 10w30 oil in it before I bought it.
 

hlw49

Lawn Addict
Joined
Jul 11, 2021
Threads
43
Messages
1,607
Yes u are right I forgot about the Silver Eagle they do have the oil light when u turn on the switch they light up until the oil pressure goes up. I never saw one flash. Guess I never saw one with a bad oil sending unit. The sending unit was really an issue with the classic. Replaced a lot of them. The sump is replaceable on the Generac engine. Too bad U gave the mower away it is fixable. Generac was a really good engine until the epa got into the act and put the emission standards on the small engine industry. Generac instead of updating the engine to meet the standards they just kept leaning the carb down to meet the standards and they started dropping exhaust valves.
 
Top