1984 Force 85 Fuel / Oil mixture

[EFT]

Recently bought this old boat. Person that sold it to me said 8 oz oil to 6 gallons of gas, that would make the mixture 100:1. Reading all other post for the Force 85 would indicate a 50:1 mixture. I had the boat out on a couple occasions and it seemed to run fine at 100:1 but I decided to mix a tank at 50:1 due to all the post that recommended it. Launched boat got about 20 foot from dock and it died and would'nt restart. I dont have the owners manual for this boat but am wondering if the 1984 Force 85 (US Marine) being an older engine does in fact require a 100:1 mixture. Found a 1983 for sale on EBAY so I asked the owner what he uses and he was kind enough to reply that he used a small bottle to 12 gallons of fuel. Assuming a small bottle is 16 ounces that would confirm a 100:1 mixture.

 

[eurolarva]

Re: 1984 Force 85 Fuel / Oil mixture

50 to 1 is the correct ratio. Chrysler was before force and they were also 50 to 1. What kind of oil did you use. Was it TCW3 marine oil?

 

[EFT]

Re: 1984 Force 85 Fuel / Oil mixture

Yes it was the Wallmart Super Tech TCW3 oil. I had used this oil at 1001: sucessfully.

 

[EFT]

Re: 1984 Force 85 Fuel / Oil mixture

Thats 100:1 successfully

 

[EFT]

Re: 1984 Force 85 Fuel / Oil mixture

So does anyone have an idea why it would quit running when I changed my fuel mix to 50:1 ?

 

[eurolarva]

Re: 1984 Force 85 Fuel / Oil mixture

You mixed 2.6 oz per gallon? How many turns out is the carb mixture setting? Could be a coincedence that it crapped out when it did. Check for spark and compression. If they are good try spraying some gas oil mix into the choke butterflies, choke the motor and see if it will fire.

 

[EFT]

Re: 1984 Force 85 Fuel / Oil mixture

I was able to contact the person I bought the boat from to clarify his instructions for the correct fuel oil mixture and it was my error in running this engine at 100:1. That said and done what do I have to look forward to from this engine? I will estimate that I ran about 24 gallons through the engine. Any suggestion as to what needs to be checked? I recently attempted to run a compression test and after reading 120 psi on cylinder # 1 my starter failed, new one ordered and I should have it by this weekend.

 

[eurolarva]

Re: 1984 Force 85 Fuel / Oil mixture

Cant do much till the compression numbers are in.

 

[roscoe]

Re: 1984 Force 85 Fuel / Oil mixture

The engine not starting may be entirely unrelated to the fuel ratio mix up.

Check compression, check spark, inspect spark plugs.

Oh yeah, check the safety kill switch.

 

[EFT]

Re: 1984 Force 85 Fuel / Oil mixture

Starter changed, compression #1 140 #2 145 #3 140.
Cleaned sparkplugs and she fired right up.
Decarbed the engine and cleaned the carbs (only carb spray through throat).
Took her out on the lake today and seems to be running just fine at 50:1.
Thanks for the reply's I believe the non starting was due to fouled plugs which were basically new with maybe 6 hours on them so I'll have to keep an eye on them. Hopefully the decarb will help.

 

[Kajun37]

Re: 1984 Force 85 Fuel / Oil mixture

change or clean your plugs after that decarb..they probably fouled again.

 

[EFT]

Re: 1984 Force 85 Fuel / Oil mixture

I did clean them