Mercury 35-HP On 13-footer - Moderated Discussion Areas

  ContinuousWave
  Whaler
  Moderated Discussion Areas
  ContinuousWave: Whaler Performance
  Mercury 35-HP On 13-footer

search | FAQ | profile | register | author help

Author Topic:   Mercury 35-HP On 13-footer

bikingart posted 01-02-2007 06:41 PM ET (US)
I have acquired a 1988 Mercury 35-HP to be installed on my 1988 Sport 13. The [Mercury automatic oiling system] has been disconnected and oil has been premixed with the gas. Is this a good thing?
The motor has a 13-inch pitch propeller. Does that sound about right for all around use? Thanks. --Art
jimh posted 01-02-2007 08:07 PM ET (US)
Automatic oil and gasoline pre-mixing systems are often disconnected, however the judgment of whether or not it is a "good thing" is subject to debate. The judgment depends on your estimation of the system's reliability. The reliability is a function of the original design and of the maintenance given to it. If the original system is well-designed and it has been well-maintained, then there is no particular reason to disconnect it. On the other hand, if the original system is not particularly beautifully designed and has not been properly maintained, it may be more a liability than an asset.
Brys13s posted 01-02-2007 09:06 PM ET (US)
I've had the oil injection system on my 1987 Merc 35 disconneced since it was 6 months old.I mix the gas/oil at 50:1 and have had no trouble.Plus it's alot less clutter{tank and hoses}which is a good thing on a 13 sport.
Tom W Clark posted 01-02-2007 09:13 PM ET (US)
I like the oiling systems in general. The OMC VRO systems in particular have proven to be very simple and reliable. The Mercury system is OK too so long as it is the second generation and not the first generation "Auto Blend" which was unreliable.
*BUT* on a little 13, I think the advantages are not worth it for the reasons listed by Brys13s and I think you are better off with using premix for simplicity.
Most 13s with that size motor use a 13" pitch propeller.
jimh posted 01-03-2007 09:25 AM ET (US)
On a 13-foot Boston Whaler the fuel tank is very likely going to have a capacity of just over 6-gallons. Pre-mixing oil and gasoline at 1:50 in such a tank is fairly simple: throw in a pint (16-oz) of oil and fill it with gasoline (6 X 128 = 768-oz). This gives a ratio of 16:768 or 1:48.
The easiest way to handle the oil is to have it in one pint containers. Buying the oil like that can be more expensive. You can always buy a few pint containers and start re-filling them from a gallon container. This will save money.
There is a tendency to always throw in one pint of oil, and if the gasoline fill is not 6-gallons, the mixture will get slightly richer in oil. For example, if you only fill 4-gallons of gasoline and use a pint of oil, the mixture skews richer:
4 X 128 = 512-oz gasoline
1 X 16 = 16-oz oil
Mixture = 16:512 = 1:32
But this is diluted with the other two gallons of 1:48, giving a total mixture of
1: 1/[ 4 X (1/32) + 2 X (1/48) ]/6
1: 1/[0.125 + 0.0416]/6 = 0.027
1: 1/0.027
1: 36 total tank mix
We used to belong to a sailing club, and our boats had two-stroke auxiliary engines. Over the course of a season, the fuel in the 6-gallon tank tended to become richer and richer because people tended to error on the side of using too much oil rather than too little oil. By the end of the season the 6-gallon tank generally held a rather rich mixture of oil and gasoline. However, if just one person is managing the tank, it will be easier to avoid this sort of build up.

The Judge posted 01-04-2007 12:32 PM ET (US)
Easy fix is use 2 tanks. When one runs dry you switch. This way you always get a perfect mix. You can also read the can and see that for 4 gals of gas you use 12 or 13oz of oil...problem solved.
RJG posted 01-04-2007 02:30 PM ET (US)
I just use one of those clear, premix measuring bottles that has the ratios printed on the side. You can put any amount of gas in your tank and then measure your oil to the corresponding line on the bottle and pour it into the tank. Hard to mess up. $3.00 at Kmart.
Boatplans posted 01-04-2007 03:34 PM ET (US)
The following comment relates to Boston Whalers or any other boat in connection with switching fuel tanks. The point made here it to allow a tank to run dry at the proper time, when it does not matter if power is lost.
As pilot of a large outboard powered pontoon boat on the Colorado River, I used a 40 horsepower tiller steered Mariner with 60 gallons of premixed fuel divided in several tanks for the 280 mile trip through the Grand Canyon. Before running Lava Falls, we switched to a fresh tank. At the pool below, we switched back to the depleated tank and ran it out on flat water.
Common sense? Well, of course.
AZdave posted 01-05-2007 12:44 AM ET (US)
The other disadvantage with a gasoline-oil mix is that you probably don't want to run it through a car or other four cycle engine. Then you have to decide how to handle the left over gas. I know there are additives, and I think the two cycle oils probably contain their own additives that retard the deterioration of stored fuel. But it is still less of a worry to burn up the last half of the tank. Dave
The Judge posted 01-05-2007 12:24 PM ET (US)
I have run 2 stroke in many cars to get rid of it. You put 5 gals of 50:1 in a 20 gal tank and it doesnt make a difference.

Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.

Author	Topic: Mercury 35-HP On 13-footer
bikingart	posted 01-02-2007 06:41 PM ET (US) I have acquired a 1988 Mercury 35-HP to be installed on my 1988 Sport 13. The [Mercury automatic oiling system] has been disconnected and oil has been premixed with the gas. Is this a good thing? The motor has a 13-inch pitch propeller. Does that sound about right for all around use? Thanks. --Art
jimh	posted 01-02-2007 08:07 PM ET (US) Automatic oil and gasoline pre-mixing systems are often disconnected, however the judgment of whether or not it is a "good thing" is subject to debate. The judgment depends on your estimation of the system's reliability. The reliability is a function of the original design and of the maintenance given to it. If the original system is well-designed and it has been well-maintained, then there is no particular reason to disconnect it. On the other hand, if the original system is not particularly beautifully designed and has not been properly maintained, it may be more a liability than an asset.
Brys13s	posted 01-02-2007 09:06 PM ET (US) I've had the oil injection system on my 1987 Merc 35 disconneced since it was 6 months old.I mix the gas/oil at 50:1 and have had no trouble.Plus it's alot less clutter{tank and hoses}which is a good thing on a 13 sport.
Tom W Clark	posted 01-02-2007 09:13 PM ET (US) I like the oiling systems in general. The OMC VRO systems in particular have proven to be very simple and reliable. The Mercury system is OK too so long as it is the second generation and not the first generation "Auto Blend" which was unreliable. BUT on a little 13, I think the advantages are not worth it for the reasons listed by Brys13s and I think you are better off with using premix for simplicity. Most 13s with that size motor use a 13" pitch propeller.
jimh	posted 01-03-2007 09:25 AM ET (US) On a 13-foot Boston Whaler the fuel tank is very likely going to have a capacity of just over 6-gallons. Pre-mixing oil and gasoline at 1:50 in such a tank is fairly simple: throw in a pint (16-oz) of oil and fill it with gasoline (6 X 128 = 768-oz). This gives a ratio of 16:768 or 1:48. The easiest way to handle the oil is to have it in one pint containers. Buying the oil like that can be more expensive. You can always buy a few pint containers and start re-filling them from a gallon container. This will save money. There is a tendency to always throw in one pint of oil, and if the gasoline fill is not 6-gallons, the mixture will get slightly richer in oil. For example, if you only fill 4-gallons of gasoline and use a pint of oil, the mixture skews richer: 4 X 128 = 512-oz gasoline 1 X 16 = 16-oz oil Mixture = 16:512 = 1:32 But this is diluted with the other two gallons of 1:48, giving a total mixture of 1: 1/[ 4 X (1/32) + 2 X (1/48) ]/6 1: 1/[0.125 + 0.0416]/6 = 0.027 1: 1/0.027 1: 36 total tank mix We used to belong to a sailing club, and our boats had two-stroke auxiliary engines. Over the course of a season, the fuel in the 6-gallon tank tended to become richer and richer because people tended to error on the side of using too much oil rather than too little oil. By the end of the season the 6-gallon tank generally held a rather rich mixture of oil and gasoline. However, if just one person is managing the tank, it will be easier to avoid this sort of build up.
The Judge	posted 01-04-2007 12:32 PM ET (US) Easy fix is use 2 tanks. When one runs dry you switch. This way you always get a perfect mix. You can also read the can and see that for 4 gals of gas you use 12 or 13oz of oil...problem solved.
RJG	posted 01-04-2007 02:30 PM ET (US) I just use one of those clear, premix measuring bottles that has the ratios printed on the side. You can put any amount of gas in your tank and then measure your oil to the corresponding line on the bottle and pour it into the tank. Hard to mess up. $3.00 at Kmart.
Boatplans	posted 01-04-2007 03:34 PM ET (US) The following comment relates to Boston Whalers or any other boat in connection with switching fuel tanks. The point made here it to allow a tank to run dry at the proper time, when it does not matter if power is lost. As pilot of a large outboard powered pontoon boat on the Colorado River, I used a 40 horsepower tiller steered Mariner with 60 gallons of premixed fuel divided in several tanks for the 280 mile trip through the Grand Canyon. Before running Lava Falls, we switched to a fresh tank. At the pool below, we switched back to the depleated tank and ran it out on flat water. Common sense? Well, of course.
AZdave	posted 01-05-2007 12:44 AM ET (US) The other disadvantage with a gasoline-oil mix is that you probably don't want to run it through a car or other four cycle engine. Then you have to decide how to handle the left over gas. I know there are additives, and I think the two cycle oils probably contain their own additives that retard the deterioration of stored fuel. But it is still less of a worry to burn up the last half of the tank. Dave
The Judge	posted 01-05-2007 12:24 PM ET (US) I have run 2 stroke in many cars to get rid of it. You put 5 gals of 50:1 in a 20 gal tank and it doesnt make a difference.