# Vintage Lawnboy: what gas/oil ratio?



## cochran51 (Jun 2, 2009)

Just restored a a 1960's lawnboy mower with a D-400 motor on it. My question is: what is a good gas/oil ratio for this old gal? I have been told everything from 16:1 to 50:1. 

Also, can I use a synthetic? I use a synthetic marketed by Honda in my little Honda scooters and it works real well. 

One gentleman on the web mentioned an oil called Opti-2 and swore up and down he mixes it at a 70:1 ratio and uses it in his commercial lawn equipment.

So confused as to what I should put in the old gal.

JOHN


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## 30yearTech (Sep 14, 2006)

As per OMC Lawnboy recommends 16:1 ratio on engines manufactured prior to 1972. 1972 and newer recommended ratio was 32:1. The only exception to this was the oil injected "M" series which injected oil and ran at various ratio's depending upon speed and load.

I would stick to the Lawnboy recommended ratio on the older D series engines, as they have a bushing on the PTO side of the engine rather then bearings.


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## Deathrite (May 21, 2009)

most of those ratios are based on older oil. i am not sure if the new stuff will do well at a high ratio. 
if you know the original weight of the oil that the unit was made in mind for you might should use that. 
just a thought anyway.


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## 30yearTech (Sep 14, 2006)

Deathrite said:


> most of those ratios are based on older oil. i am not sure if the new stuff will do well at a high ratio.
> if you know the original weight of the oil that the unit was made in mind for you might should use that.
> just a thought anyway.


For many engines I would agree, but the last service update I attended for Lawnboy (about 4 years ago) emphasized these ratios for the older engines. One can of course take their chances with newer synthetic oils, they may be just fine at the higher ratios.


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## Deathrite (May 21, 2009)

wow. Lawnboy had a service update? nice!

and thats kinda why i mentioned the what weight was the oil then idea... 5w-20 might work different then 10w-40. 

it would be interesting to mix a newer oil at the higher ratio and see what happens. 

too bad i cant get that old lawnboy 2 cycle we got to run.


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## geogrubb (Jul 28, 2006)

Deathrite;
If you have an old Lawnboy and it has spark and compression it will run. Have a good one. Geo


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## Deathrite (May 21, 2009)

old lawnboy. last we looked (and if i recall right) no spark, low compression, kill switch was discontinued, and i seem to think the carb was rusted a good bit. OH and the cable to the kill switch was going to cost us (dealer cost) over $55. 
if we get another one in might can make two from one.


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## DIPSTICK 101 (Jul 12, 2010)

i just picked up a gold 63 lawn boy . it has a round 18 emblem and a model num3052. it also has english and french warnings on the front of deck. has what apears to say dmg on side of moter. any info at all would be of great help. thank you very much


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## 30yearTech (Sep 14, 2006)

DIPSTICK 101 said:


> has what apears to say dmg on side of moter.


Sure it's not "OMC" on the side of the engine??


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## 2 cycle (Jun 28, 2020)

Deathrite said:


> wow. Lawnboy had a service update? nice!
> 
> and thats kinda why i mentioned the what weight was the oil then idea... 5w-20 might work different then 10w-40.
> 
> ...


I have some 2 cycle lawn boy oil in cans if you want to buy it.


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