how to get the most out of my inline 6 mercury 1350 1971

[madmark454]

i have a 1971 inline 6 1350 hp it is a nice motor runs strong it has 150 lbs of compression across all six cylinders. im in the process of setting my boat up and proping it now but i cant find to much info about these motors cuz there so old is there any like lil tricks or stuff to watch out for in order to get the best performance? im running it on a 750 lb boat and im getting 52 mph does this sound about right or can this motor do more? (no jack plate and im running a aluminum prop) and are these motors turds out of the hole compared to a new outboard low end torq wise?

 

[madmark454]

Re: how to get the most out of my inline 6 mercury 1350 1971

and how much did u retard ur timing? i also herd this motor i have they did sumthin diffrent as how it burned fuel they up the compression and changed the cumbustion chambers or porting but i only found that ounce and havent seen n e thing else about it.

 

[madmark454]

135hp 52 mph?

135hp 52 mph?

i have a checkmate predictor 750 lb hull 16ft with a 71 135hp inline 6 merc no jack plate short shaft engine is 52 mph slow or is that about right?

 

[j_martin]

Re: how to get the most out of my inline 6 mercury 1350 1971

Now you're into high performance setup. You need to pay pretty close attention to timing and mixture to keep from grenading it.

These engines like to spin up. They don't do well lugging. A good stainless prop that has some relief, either ventilated, or exhaust over the prop design would help a lot by letting the engine spool up quickly into the power band for the hole shot.

An aluminum tug-boat prop on your setup is pretty silly.

hope it helps
John

 

[j_martin]

Re: 135hp 52 mph?

Re: 135hp 52 mph?

How many threads are you going to start on the same subject?

 

[madmark454]

Re: 135hp 52 mph?

Re: 135hp 52 mph?

i couldnt find my other one i actually wanna get a bunch of people hittin this and see if i can get some good info cuz there are not to many people that are into the old inline 6 engines. am i only alowed to post 1 thing? do u do security on here?

 

[madmark454]

Re: how to get the most out of my inline 6 mercury 1350 1971

ur beard is silly! but thx for the info. and im running aluminum props to get me in the ball park as far as pitch dia and hitting the rpm i want so i dont have to buy a bunch of stainless props to find the right one.

 

[Chris1956]

Re: how to get the most out of my inline 6 mercury 1350 1971

52 MPH is likely in the ballpark for max speed, depending the type of hull you have and whether you have power trim. What pitch prop are you running? What was your max RPM?

BTW - this site had a sale earlier this year on pretty good aluminum props. They are drilled for controlled ventilation, as John has recommended.

 

[Faztbullet]

Re: how to get the most out of my inline 6 mercury 1350 1971

If you have the original gearcase it will be a little slower on hole shot as it is a 1:78 ratio vs the 2:1 that came on all the other inline six's. Dont spin it up as max rpm is 5400rpm and operating range is 4800-5400rpm. It and the 1150 of 1970-71 is the first inline to have "direct charging" induction. About 50 mph is all your going to get with that set up as its only putting out about 110hp at prop.Your best all around prop would likely be a S/S 22pitch laser II...

 

[j_martin]

Re: 135hp 52 mph?

Re: 135hp 52 mph?

You can post as often as you like. If you post more than one thread on the same topic, in this case, "how can I make this rig run faster or is it there", you discourage busy people with the most to offer from posting. My thinking is, "Why bother trying to help someone who can't seem to keep track of his postings."

If you read your own post, it then will not be highlighted. Your other post was only a few lines down from this one, like about 15. This forum runs about 4-8 pages a day in the Summer. It settles down to about 2 in the Winter.

 

[Faztbullet]

Re: 135hp 52 mph?

Re: 135hp 52 mph?

Its about right.......