Al Stoker builds a 300 HP Evinrude V6 in Hotboat

[perfmarine1]

Back in the mid eighties I had a buddy that wanted to modify his 78 235 so we sent the motor to land and sea ,it was in bad shape,so they board it out and sleeved it to A160 put some high compression pistons in it 255X heads boared carbs 10 port reed cages ,Can removed ,megaphone shorted,board carbs,balanced assy, 2 1/2 inch hole drilled in mid section,and a 77 v4 gearcase with nosecone lwp. We got the motor back assembled it and the 2 cylinders leaked water Into the intake side of the motor so we sent the block back to Land &sea,they confirmed it and gave us a brand new 160 block for cost,board to match the high compression pistons. Running on 98 octain as per L&S . They told me it would make 265 horse. He ended up putting it on an 18' skater And the boat ended up too heavy for the motor porting. So I traded him a 1970 SS Nova for the motor pick myself up a brand new XR 2002 Allison and I butt hurt so many Mercury race guys it wasn't even funny. Especially since I had a150XP evinrude cover on it. It would make about 10 passes and then I had to put a gear set in the gear case.

[STV_Keith]

I saw Al at the Havasu race in October...I swear he doesn't age! Nice throwback article.



Also interesting to note the B&D Marine ad on page 2 of the article. RIP to Brian Fetherolf who lost his battle with cancer earlier this year. **** Cancer.

[Forkin' Crazy]

It didn't happen often, but I have seen a few mercs get humbled by a OMC.

How many by 35 year old dinosaurs? The XP I built to run super stock ran better than the 235. I heard "My mota's missin'" too many times...

The carb/tuning is the key. Mr. Stoker taught me what to do, and what parts to use... He was so nice he even coached me on the phone... I have all the notes written down.

[JBS]

I bought a 78 20ft Allison SS it had a 235 that supposedly went to LandnSea. Boat ran strong ,when it ran.Very temperamental.Relaced it with a 200 xp an had a good reliable boat. That set up was 3 mph faster than an identical boat with Merc 200 .

[Instigator]

Gotta remember, the OMC cross flow was top of the food chain for the late ‘70’s - early 80’s era.

They had the low end-mid range that a Merc didnt and the Xp/Gt’s had the top end on them too.
Then if a sharp tuner (the Stokers of the world) got a hold of one, you had a screamer.

I had similar experiences w/a Xp 2.6 Rude as JBS did.
That block had been to L/S multiple times.

Unfortunately that was before I understood tuning a 2 stroke.
Its Achilles heal is the deflector/knuckle on top of its pistons that “deflect” intake from
exhaust charges.

That made the pistons very heavy.
When running under high load, it also made those knuckles, red hot, glowing ingots trying to burn it down!

Then when you mod one, which mine was, you are on the ragged edge of burn down.
A bad load of fuel, too much wheel…., youre done!

Ironic that the Merc crowd spent decades bashing the hated “cross flow” when guess what all of the Mercs were from the “tower of power” down?
You got it.

Then when the V-6 Mercs replaced them, guess what they were?
LOOPERS ������

I spent some time talking (listening) to Al and his opinion on them.
As I recall:
In “marathon” tune, he felt the max was 260ish HPs, and high 6k revs.

In “sprint” tune, 280ish HPs and low 7K revs.

He told me he thought the secret was to port one to think it was a looper.

I consider those damn good numbers, especially when considering that the Merc 260 was probably the most popular Hi Perf OB of all time.

Also like JBS, I switched to a looper.
Bought a new GT 200 in ‘89 and picked up 3 mph and total bullet proof reliability w/the change and never went back.

To be fair, I cannot be sure what level my XP was really at.

One of the funniest things I saw was on a Merc powered STV in Fla yrs back.
Its owner had a sticker on his boat of a guy pissing on a OMC looper.
I didn’t have the heart to tell him his mythical Merc was also a looper ��

[LaveyT]

The Really cool thing about Al is he is always there to help. He always chimes in on the Stoker Boats face book group when a question is asked. And always willing to help on an OMC build or tuning question. One of my Hero's for sure!

[FMP]

https://www.screamandfly.com/showthr...1-Reeds/page9&
> First a little about the engine used for the test, it is a 183 cubic inch production based engine basically built to ODBA pro carb rules minus compression and a modified intake. It was tested with 155 psi compression and untouched intake manifolds, reed cages were lapped for inproved seal. Stock factory ignition except for a race flywheel. Mid section used was stock except for water routing needed for dyno use.
>
> Dyno is a superflow with windyn data, room is about 12X18. Exhaust is thru a large muffler (city req.) and water supply from a 10K gallon tank, I thus can control water feed in volume and pressure to the engine cooling. Air parameters for the test were very close.
>
> A base line beyond test parameters was established before the high compression heads and modified intake were removed, in this trim it made 400.5 horsepower after testing was complete it was retested to verify condition of engine and it made 399.4. After each reed test compression and leakdown were performed and they remained very consistent. If a test was done on a different day, the previous test was rerun to verify accuracy, no change more than .5 horsepower was noted.
>
> Tests were run using 110 race fuel and 40 to 1 oil. Tests were controlled to the best of my ability including engine temp, I am including one run at a lower temp so you can see the difference it makes. All reeds were cycled thru different rpm ranges to verify reed durability, then a minimum of three pulls were performed.
>
> First reeds tested stock prodution steel reeds with stops.
> Peak torque 286.9 @5800
> Average from 6000 to 7500
> Torque 264.6 HP 338.8 Pounds fuel hour 197.7 BSFC .606
> Average from 6500 to 7500
> Torque 258.8 HP 343.6 Fuel 191.2 BSFC .577
> Engine temp 128 degrees Horsepower fall off from peak to 7500 -19.6HP
> EGT 1090
>
> Second reeds Boysen 166 no stops
> Peak torque 298.3 @5500/5800
> Average from 6000 to 7500
> Torque 275.2 HP 352.8 Fuel 212.7 BSFC .625
> Average from 6500 to 7500
> Torque 269.1 HP 358.2 Fuel 207.2 BSFC .599
> Engine temp 129 degrees HP fall off peak to 7500 -4.2HP EGT 1070
>
> Third Chris Carson .022 yellow with stops at 128 degree temp
> Peak torque 283.2 @5600
> Average from 6000 to 7500
> Torque 264.1 HP 338.5 Fuel 196.6 BSFC .603
> Average from 6500 to 7500
> Torque 258.9 HP 344.5 Fuel 196.6 BSFC .592
> Fall off 14.8 Hp EGT 1090
>
> Same reeds at 119 temp
> Peak torque 288.2 @5700
> 6000 to 7500
> Torque 267.7 HP 343.2 Fuel 191.8 BSFC .577
> 6500 to 7500
> Torque 262.4 HP 349.3 Fuel 192.4 BSFC .569
> Fall off Peak to 7500 -11.6 EGT 1090
> So you can see temp also effects these engines
>
> Fourth TDR .022 white with stops
> Peak torque 291.2 @5600
> Average from 6000 to 7500
> Torque 267.8 HP 343.2 Fuel 202 BSFC .615
> Average 6500 to 7500
> Torque 261.9 HP 348.4 Fuel 198 BSFC .591
> Engine temp 126
> Fall off peak to 7500 -7.8 EGT 1090
>
> Of note,
> All averages done by the computor, accel rate same for all and controlled by the computor at 600 rpm gain per second
> All reeds in tack after test but Boysen had a few slightly open, causing a slight spit on restart
> Best idle quality and starting Carson and TDR
> Loudest intake noise Boysen
>
> I am going to try and test thinner race type reeds on cut cages once I get some time including some sent that did not meet this tests parameters, one already tested. The above are reeds that should live well in every day use. Pictures to follow in a few days.
>
> I would like to thank both Tony and Chris for their participation in this test. Total time involved 16 Hours two guys, fuel burned to much.

[Allan 204SST]

Looking good!!!

Who has a looper that doesn't have that article?

And what about the Crossflow OMC 9 pages? I have a copy of that in PDF if anyone wants it.

I talked to him at length about crossflow carbs long time ago. Awesome fellow!

Hello, I was hoping I could get a PDF of the Crossflow OMC article you have? I’m very interested in what Al wrote about it. He serviced my Stoker up until their retirement. Sadly I could not afford the hot rod stuff back then. Much appreciated, Allan

[Stoker1]

March 2003. This should bring a smile to Instigator.

Did you get this off of FB? If so, that was me that posted it

[David]

Did you get this off of FB? If so, that was me that posted it

Nope, I scanned a magazine that I had. I think I posted this before your post on Facebook, but it doesn't matter - it's a really cool article, so the more that see it the better.

[Stoker1]

Nope, I scanned a magazine that I had. I think I posted this before your post on Facebook, but it doesn't matter - it's a really cool article, so the more that see it the better.

Seems we were on the same wavelength. Also looked at yours more closely and noticed they were framed much better.

[wolfgangb]

March 2003. This should bring a smile to Instigator.

what is part # 322812 for the carbs?
Thanks in advance for answers.
Rgds, Wolfgang (South Africa)

[racer]

Wolfgangb that number is for the pull over tube that gets installed just below the venturie.

[wolfgangb]

Wolfgangb that number is for the pull over tube that gets installed just below the venturie.

Hi Alan,
I do thank you very much for your prompt and helpful response.
Now that you mention it, I recall that years ago there was a short thread here on S&F, which showed the position of the mod. Was this a "Service Bulletin Procedure" and where/from who might I be able to get the parts/procedure?

[racer]

Part is no longer available so will need to search for them.