Promax block crack ???

[roadkill636]

So I bought a Promax and once I got it home and rubbed a bit of oil off the block I found a crack and these 2 holes at the bottom of the block. Not sure if the seller knew about it or not. Looking thru the searches and found that someone else had a block that had the same crack same place but got it welded and the Merc repair guy said that they crack there regularly.
Did I just buy a anchor? And what's with these holes?

The pic with the weld is from another thread another member here .

[Dave S]

I shoot..... many ..... blocks....... Just my frustion.... Leter Reip...... times we live in......

[rock]

The holes are unimportant and I think that weld pic is of my promax (Hydrostream in the background). Mine was done to prevent the crack.

Rock

[roadkill636]

Yes Rock that is a pic from your thread. But my Blood k has cracks and I dont know about these promax blocks and what is on the other side of the crack. Is it just a simple exhaust leak? Is it a ph stud? Is it in a water jacket that will get into the exha8chest and cyl?

[rock]

I have one in the shop and will try to give it a look tomorrow. Seems like it's about the stud in the exhaust. Remind me if I don't get back to ya. Working in the same building as the shop but not in the shop right now. Hangin a bunch of sheetrock tomorrow.

Rock

[Capt.Insane-o]

They usually happen when the person doesn't pick the powerhead straight up off the adapter plate or tightening the block down and it isn't seated properly. As much those are the last 4 nuts you tighten and don't get all king kong on the wrench.

[rock]

I have never had one break and freaked when the block came back with the weld on
it. This site is where I learned it was preventive. Never know what you'll learn here. Some of it even useful.

Rock

[tlwjkw]

never "cracked one" with nut install but have with stud install.. never heard of it done as a preventive measure.. if its welded its been cracked.. story sounds good though.. :reddevil:

[tux974]

Mercury started making a tad longer studs with more threads just on the course side exactly for that reason! Deeper into the block since its a very thin area back there.
If you look up the 280 PH studs you will see different part #'s....... 2- 2 1/2" and 2- 2 3/4".

[tlwjkw]

:thumbsup:.... exactly.

[roadkill636]

Question is. Is this crack likely to go thru a coolant passage and or exhaust chest and able to get back up into the cylinder?

[rock]

Block was not cracked before we sent it to Gene at G Force. Man did good work but was not a good businessman. Kind of like Ron.

Rock

[tlwjkw]

his idea or yours?.. jus one side?.. jus courious....

[tcrabtree]

Promax blocks are very prone to this. I Have 1 that cracked in the same spot & have saw several others. Weld it up & install a gusset to strengthen it , no big deal. Never Over torque the back 2 studs, that will cause it.

[rock]

Both sides Gene's idea. Like I said I freaked when it came back with welds.
Rock

[tlwjkw]

good man... reason I asked once I had a shop call to tell me they had cracked it on one side when they attached it to a fixture.. fixed it and put a weld on other side.. also good folks...

[TEXAS20225]

JIm ruck did this to two of my 225 pmax blocks and james fixed one for me with the leg to support it i have seen them do the same thing on 200 efi blocks not too often but still required welding up im am thinking its produced by over tightening back two nuts also

[roadkill636]

I'm still looking for the question that was asked in the 1st post... is there a water passage that this crack is near or in that will let water get into the exhaust chest and somehow get into the bottom cylinder?.

The motor has been running the past 9 years the owner stated.

I dont want to tare down the ph if it's just cosmetic and not going to hurt anything more staying like this

[Hydrodreams]

Pulling mine down now. Never rebuilt 1997 ProMax with a bunch of hours. Has a crack in the same spot on the port side.
https://www.screamandfly.com/blob:https://www.screamandfly.com/10144e19-cfb7-41d7-8400-d591feeeb93c

I will upload a picture later. Not close to a water passage for the above post. Just a thin spot in the block and you can see where mine has been exhausting through the crack.

[tlwjkw]

I'm still looking for the question that was asked in the 1st post... is there a water passage that this crack is near or in that will let water get into the exhaust chest and somehow get into the bottom cylinder?.

The motor has been running the past 9 years the owner stated.

I dont want to tare down the ph if it's just cosmetic and not going to hurt anything more staying like this

I've never seen it cause a problem with water stuff... but there is always a "first" with merc………………..:reddevil:

Bobby, have ya closed up shop?.. ya "new ta me" fancy gate always closed?...…….

[tux974]

This has been going on for a long time the 245/260 blocks were also notorious for cracking back there. Hence why long studs were introduced.
The 2 factors I have found to be the culprit are, removing the power head improperly and not using enough studs when using/installing to a fixture.
Roadkill, Never seen it affect water passage.

[Dave S]

Just buy Yammi.....

[Hydrodreams]

Here is the crack in my block..
453541 453542

[Dave S]

Not sure.... if Promaxk.... HeeHee......does.... twinnn gasket with a pan..... but that could.......if not....

[Dave S]

And...... Why...... do L6 Mercs have Cracks.... on the..... transfer hole........V6.... 150 and all....have cracks on the exhaust web??????Speek to Me Scotty......More power th tha front blasters.....silly bunny....Harminicks.......Sorry for the fact that I don't spell.....

[tux974]

Hydro, I say that needs to be welded.

Dave,
Yes PM's have Hi-Perf double gaskets with either pan plate, old style and alien.
Yes, also common V6's have hair line cracks in exhaust web.

[Dave Strong]

Hydro, I say that needs to be welded.

Dave,
Yes PM's have Hi-Perf double gaskets with either pan plate, old style and alien.
Yes, also common V6's have hair line cracks in exhaust web.

Almost looks like a casting void that cracked??

Dave

[tux974]

Almost looks like a casting void that cracked??

Dave

Dave Yes, and only can be seen with plate off.
That area even on a good casted block is very thin.

[Merc 2.5]

Here is the crack in my block..
453541 453542

One of these pics looks like it could have been losing sum exhaust. from the coloring neway

[roadkill636]

My plug on top of the block is blank. I thought all Mercs had their numbers stamped in there. What's up with this one?

[Merc 2.5]

Maybe a Reman. #s behind throttle arm?

[tlwjkw]

"pot luck" with it being stamped with any kinda identifying number.. never heard and/or found out why some got 'em and some didn't.. rumor has it if a run of "complete motors" was known it got tha serial number that matched clamp.. if a run of powerheads only that would be matched to a clamp later didn't... who knows its merc……………………………………………..

[Dave Strong]

Most times " race " motors stamped by timing arm with ser number where case halves meet. Fishing motors on the frost plug.

Dave

[tlwjkw]

:thumbsup:

[Hydrodreams]

[QUOTE=tux974;3175427]Hydro, I say that needs to be welded.

Thanks Tux, will do!

[tunnelmike]

Marine Machine in Gonzales adds a longer stud there to get beyond the crack. Once cracked he recommends welding inside and outside.

Bottoming out the stud makes sense as a culprit. I've pulled plenty powerheads on weird angles and never broke a fishing motor there over the years

[tunnelmike]

Marine Machine in Gonzales adds a longer stud there to get beyond the crack. Once cracked he recommends welding inside and outside.

Bottoming out the stud makes sense as a culprit. I've pulled plenty powerheads on weird angles and never broke a fishing motor there over the years

[eli]

Is what they have tig welders for

[Merc 2.5]

Marine Machine in Gonzales adds a longer stud there to get beyond the crack. Once cracked he recommends welding inside and outside.

Bottoming out the stud makes sense as a culprit. I've pulled plenty powerheads on weird angles and never broke a fishing motor there over the years

So how is that marine machine ? They do good work? I've been looking at them to send a block to but didnt no if anyone had experience with them

[tlwjkw]

Bottoming out the stud makes sense as a culprit. .. 99% of tha time plus

when ya gotta testosterone full gorilla on tha other end of tha stud ratchet...………..

[TEXAS20225]

HEY Tommy how you doing mister Happy Thanksgiving and yes i closed it down after Barbara died in September i just lost all the wind in my already leaking sails, i was so tired of dealing with people who did not need to own a boat!!! building only motors and no service work eliminated a lot of exposure to that group it was still very difficult to deal with those who thought a brand new whole motor was worth about 2500.00 installed broke in and full of gas with a 10 year warranty i had already slowed way down in early 2018 bout January

[tlwjkw]

dammit, so sorry ta hear 'bout barb.. prayers n good thoughts to ya brother.. will be glad ta see 2019 gone....

[Merc 2.5]

HEY Tommy how you doing mister Happy Thanksgiving and yes i closed it down after Barbara died in September i just lost all the wind in my already leaking sails, i was so tired of dealing with people who did not need to own a boat!!! building only motors and no service work eliminated a lot of exposure to that group it was still very difficult to deal with those who thought a brand new whole motor was worth about 2500.00 installed broke in and full of gas with a 10 year warranty i had already slowed way down in early 2018 bout January

Damn bobby. 10 yr warranty on rebuild?? That alone should say sumthin

[TEXAS20225]

10 year warranty was a figure of speech used as a example of just how stupid some people are when you rebuild there blown motor usually due to auto oiler failure (who's fault is that) and you give it back to them with ALL THERE ORIGINAL PARTS INSTALLED ON THE REBUILD there parts become under your warranty ???NOT ive had several battles like that people calling me up cussing me out calling everything under the sun so yeah its time

[Dave Strong]

HEY Tommy how you doing mister Happy Thanksgiving and yes i closed it down after Barbara died in September i just lost all the wind in my already leaking sails, i was so tired of dealing with people who did not need to own a boat!!! building only motors and no service work eliminated a lot of exposure to that group it was still very difficult to deal with those who thought a brand new whole motor was worth about 2500.00 installed broke in and full of gas with a 10 year warranty i had already slowed way down in early 2018 bout January

So sorry to hear about this, 2019 has been a crappy year forsure. Happy Thanksgiving and hoping for a great year in 2020.

Dave

[W2F a V-King]

So sorry to hear this Bobby.

Prayers up for you.
Been a tough year for many ....

James

[tunnelmike]

Sorry for your loss.......


Marine Machine in Gonzales La has been doing great work for years. They did my first motor 20 years ago thru Simon's Outboard and everyone since. Fair prices and honest assessments. Full service outboard machine shop. Mike

[Merc 2.5]

Sorry for your loss.......


Marine Machine in Gonzales La has been doing great work for years. They did my first motor 20 years ago thru Simon's Outboard and everyone since. Fair prices and honest assessments. Full service outboard machine shop. Mike

Thanks was hoping sumone had dealings in past with them. Did they do extensive block work and such for u?

[tunnelmike]

Nothing too major. Took an xri motor and opened up the exhaust and on a Pro Max 225 I had they basically turned it into a 245. Had carbs on it when I got it. Ran 113 on my Mirage. Only got 115 with a 260. I was impressed.

Xri was in 99 and still running. Pretty sure the Pro Max done in the early 2000s is still going. Sold out to race ss is the only reason I let it go

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