Omc 300 v8 on 21 action?

[21action]

It says 1987. I'll have to double check when I see tomarrow. Any idea what they should be for 3.6 or 4.0.

[Markus]

Seams like it's a mixed of people that like em and others that don't.

The V8s are indeed a mixed bag. Think of it like this:

Pros
+ Great opportunity to learn how to troubleshoot engines. That is a lifelong, valuable, skill.
+ You will get lots of new friends as you look for parts
+ Good for the environment with an engine that isn't running

Cons
- Having the least reliable engine of its era means spending less time boating
- Most people trying them are surprised by the minor increase in performance
- You will spend a lot of money to feed it with parts
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[Riverratt]

Just curious as to the people commenting on this thread how many of you actually owned and have first hand personal experience with them? I owned on for over 10 years and have never experienced all this bad stuff. If you want the V8 get it. They are unique and they get many comments. They do like their fuel. if you are buying one thinking you are getting the performance of a 300x then you will be disappointed. You roll the dice on any used motor doesn't matter the flavor. If I did went by online reviews on everything I bought i would never own a thing.

[Merc 2.5]

My argument to the fuel consumption always was, compared to what?

So At 3/4 throttle your 300 V-8 is using more fuel than your 2.4/2.5?
If that’s the issue then......(I like math)

In theory, @ 3/4 throttle, your 200 is making 150 HPs.

Conversely, your 300 @ 3/4 throttle should be making 225 HPs correct?

So your 300 is now making more power at 3/4 throttle than your 2.4/2.5 is even capable of making @ WFO but is not allowed to burn more fuel??

I always liked the math of:
10 HP = 1 GPH.
Period.

Back to you guys ��

I havent really been keeping up with this thread , but I would think fuel mileage should b irrelevant, for 1 being a big 2 sroke (and carbs) wether its omc or merc , they drank gas like there's no tomo, 2 if your worried boit fuel milage ,get a bigger tank or a 4 stroke "I guess? Ha" all I know if I had all the stuff laying around to swap it and try it , lord knows I would just to have the 1st hand experience, u can always go back , I've had boats way over rated with motor and would swamp boat bad , had to turn out of the slow down so wave would pad you , I did have em die couple times at speed and have to run to front of boat b4 it set down. But like any other boat u will learn it if its stern heavy. Sorry for long post , just couldn't agree more on fuel stuff , I've had both and both is bad , especially when u start modifying and putting more fuel to em

[Markus]

Just curious as to the people commenting on this thread how many of you actually owned and have first hand personal experience with them?

Have friends who have had them, going back to when they came out. Also spent a lot of time with a dealer who sold more of them than anyone else in the country.

Now back to enlightening potential owners on the joys of owning one. <object id="__symantecPKIClientMessenger" data-supports-flavor-configuration="true" data-extension-version="1.0.1" style="display: none;"></object>__PRESENT

[Markus]

I have an idea on compression but I’ll let the experts that have been bashing them for the last 2 pages tell you.

You have no use for compression until you have spark and fuel.<object id="__symantecPKIClientMessenger" data-supports-flavor-configuration="true" data-extension-version="1.0.1" style="display: none;"></object>__PRESENT

[mrichartz]

Don't listen to all the negative crap...if you want one do it
If your worried about fuel you have the wrong hobby..lol
They are really cool motors...and down the line when you have saved up some cash for a little extra/lot hp send it out and can have a beast of a motor...

[Da Bull]

...instigator, you gather everything you need for your V-8, to get it going? what midsection length you going with? you prefer the johnson cowling or the evinrude cowling? did you get any powerhead accessories with the powerhead you bought?

Just thinking out loud here but I can`t recall ever seeing a 20inch V-8 cut down to 15inches. I know someone`s bound to have done it. My guess is that a 3.6GT mid would look cool as hell. Calhoun Marine cut a offshore ridgeback mid to 15 for my Bridgeport and did a great job w/vertical straps welded in several places.

[mrichartz]

Just thinking out loud here but I can`t recall ever seeing a 20inch V-8 cut down to 15inches. I know someone`s bound to have done it. My guess is that a 3.6GT mid would look cool as hell. Calhoun Marine cut a offshore ridgeback mid to 15 for my Bridgeport and did a great job w/vertical straps welded in several places.

Trying to find the pic I have of one cut ..and yes it does..it's actually some that Calhoun did think it was 16"

[Instigator]

To the nay sayers:

The 8 is two V-4’s starched up.
There are millions of 4’s still going so why are the 8’s junk?

Two more cylinders than the V-6 loopers, of which, millions are still going strong.

Bashing an ignition, most of which are over 35 yrs old, really??
Same **** bashing the 6’s.

A guy buys an all orig, 30+ yr old motor for $1500 and bitches when it doesn’t run right?
I ignore those experts.
They give up and buy a 2.5 anyhow.

Markus, know how many 6’s and 8’s I’ve helped sort that we’re just out of tune??
95% of those, by someone w/no experience with “link and sync”.

When it starts hard or idles poorly, the first thing they do is advance the throttle linkage.
Worst possible thing.

This opens the throttle plates (one per cylinder) which opens the mid range circuit in the carbs.
Those motors are designed/tuned to start and idle w/closed throttle plates.

In addition, the dual power packs y’all are bashing?
They are V-4 packs.
So why do they suck on an 8 and shine on a 4?

Ive seen dozens of 8’s, here in the mid west and in Fla for 9 yrs I lived there, with 1000 - 1500 hrs on them and never been apart.

Theres an ‘86 V-8 on a 25’ fishing boat by me that’s all orig, never apart and runs like new.
I’ve been trying to buy it but owner loves it, saying it owes him nothing.

When I buy a new project motor I buy all new ign comments and rebuild all the carbs.

When I was young and poor, I swapped used components until I got it to run like many on here do.

You need to go to Fla and see how your 35 yr old Yammis are doing.
Ive posted pixs for you, of stacks of dead V-6’s.
Ive worked on them that you couldn’t get a single bolt out.
Tiller arms rotted completely through!

Want to see how good a motor is?
Put it in an area w/365 day boating seasons, 95* heat, 95% humidity and in salt water for 10 yrs.
Then come find me.

Want me to remind you of the two five yr old 4 stroke Yammis in my old Fla neighborhood that were toast due to the above?
The block on the 250 was rotted so bad, it was spraying saltwater on the bottom of the flywheel/ignition!

Still remember the look on the owners face when I showed him.
Both motors had note books documenting factor spec’d preventive maint!

I have a friend down there, that is getting rich welding up rotted out Yammi blocks.

Your 3 decade, blind hatred of all things OMC is well known on this board.
You clearly have no clue what the fk your talking about so why stink up a guys thread that’s looking for legit advice?
Since you hate OMC’s, why post on their threads?
Just makes you a key board expert, same as the rest.

I have a ‘85 (first yr) V-8 powerhead in my shop that has one bad hole due to previous owner leaving a fuel line loose on a carb after rebuilding them.
Other than cutting the heads, it’s a box stock, 35 yr old motor.
For grins, I ran compression.
It has 147 lbs (on a good digital gauge), exactly, on the other 7 holes!
35 yrs old!

Being the first era 8, it’s the same as the first two yrs of V-6 loopers, in which the sleeves are thick enough to go from its 3.6 liter orig capacity to 4.0 liters and stock bore V-6 pistons.
If your going to bore it anyhow, there’s 400 cc’s for free.

You can buy a complete V-8 for $1500, $1000 for new ignition, $200 to rebuild all 8 carbs (assuming doing it yourself) , $500 for new paint and graphics, $1000 to add finger ports and have $4300. in a 400 hp, 7500 rpm, pump gas monster that will pull up 4 slalom skiers!
And have something no one else does.

Skip the paint and finger ports and have 350 HP’s w/the same torque for $2800 and paint it later.

[mrichartz]

Well said.. and X2 Exactly...and yes everyone who bitches about ignition how bad they are..they are swapping old parts and can't understand why still run like crap..and some people just need to **** all over something..instead of being helpful

[FUJIMO]

...if you decide to go ahead with this project, may i suggest keeping the boat powered the way it is for now, and then go ahead and put together everything for the V-8, rigging parts included, then take off the motor & derig the boat all at once later, when the V-8 is running & ready to be rerigged to the boat...just an idea.

[mrichartz]

But hey if anyone has a v8 they don't want..!!!

[Markus]

some people just need to **** all over something..instead of being helpful

I am being helpful. I am trying to help someone not to go into the trap of getting an OMC V8 because they think it is cool to have a V8. Too many people have done that and come to regret it.

We know that:
1. Ignition components were not good even when they were new. V4 and V6 ignitions were not good either - that's why people replace them with Yamaha ignitions - and there are fewer parts that need to work at the same time on those engines than on a V8
2. OMC warranty costs for the V8 were huge back in the day - far higher than the 3.4 liter Mercury V6 that was its key competitor. And nobody thinks that it is a good idea to get a 3.4 liter Mercury
3. They had to sell the engines at a huge discount through the backdoor (Second Effort) to get rid of them
4. They stopped making them due to lack of demand and scrapped the tooling
5. The company went out of business due to poor quality

It all points in the same direction.<object id="__symantecPKIClientMessenger" data-supports-flavor-configuration="true" data-extension-version="1.0.1" style="display: none;"></object>__PRESENT

[mrichartz]

How did you know I was talking about you..do you sh** on all omc posts...smh that's not being helpful ALOT of people have them you going to talk everyone out of them..
Well Sh** that's ok I'll take them.
Like Gary said just because you have a hatred of omc don't go ****ting on his post..
Then need to get the right parts not hard. V6s...had my last motors for over 16 years had 1 power pack go bad and was that was it. Out of both motors..it took one motor eating a reed stop to kill it and I was not easy on them.
Usually when I've seen problems it's someone forgetting something or trying to screw w the motors and don't know what they're doing.
I don't give a crap about warranty this or that your talking about 35 years ago..price point on getting one, then if you decided to really build one hell of a motor digital ignitions..have had them for awhile because I was building the ones I have now..
Definitely worth it the money to upgrade.. they start a tap of a key because spark comes from battery now and fixes all the other stuff people said we're problems..
It's called upgrading
If they are swapping to yamaha ignitions why not buy a Yamaha..
Your not talking about the same situation as 35 years ago buying a new one at 8-10g yes I forget how much they were ..it's a different situation 35 years later.
we are looking at a V8
That you can get for less than the price of the cowling of a new v8 or 300hp probably alot less