Can a 225 promax use a 260 block?

[hunter0402]

I have recently purchased a 20xrd bullet with 225 promax. It runs mid 70s which i understand is a little slow. It also is not getting correct water pressure and giving an overheat alarm at the end of a long run. These things concerned me so i took it to a mechanic and he tells me that the motor that i have has been rebuilt with a 260 block and is a ticking time bomb. My question is if this is correct information. He tells me the motor is basically a parts motor with this modification. Any advice would be greatly appreciated.

[wired247]

Before you get too excited about anything keep in mind that sometimes mechanics arent that good at what they do for a living. Happens. If he was actually good at what he does for a living he'd figure out what was causing your motor to overheat with the combination of parts you have. Could be a number of things starting with the water pump impeller. First thing you need to do is a little leg work. What are the serial numbers on your block? There should be a plug on top of the starboard side with the serial numbers stamped in it.

[tlwjkw]

There should be a plug on top of the starboard side with the serial numbers stamped in it.

Hi Perf is gonna be on tha mating block/front half flange on tha port side by tha throttle/timing arm..........If its a replacement block it will have some strange numbers on it instead of a "normal" serial number.

[wired247]

Hi Perf is gonna be on tha mating block/front half flange on tha port side by tha throttle/timing arm..........If its a replacement block it will have some strange numbers on it instead of a "normal" serial number.

I'm on the working assumption that his mechanic is full of "mistaken" and that is actually a 225 block.

[tlwjkw]

That "includes" tha Pro Max. ANYTHING outta Hi Perf......................

[hunter0402]

The guy is reputable and good at what he does. Everyone i know in the mercury world around here recommended him. I think he builds around 50 motors a year. My concern is if the motor is actually a bomb or if this combination will last. He informed me that the overheating issue is due to water routing on the block is different than the promax in conjunction with having a 2 hole cle lower unit that does not pick up enough water for the motor. He also sells motors that he has rebuilt and wants to sell me one of them. I'm wondering if anyone can give me some insight on specifics to why the 260 block doesn't pair with the 225 front. The motor runs fine as far as i can tell. If i change my fuel ratio to 35:1 i don't get the overheat alarm. My boat is not with me right now or i would get the serial number though i have done some research and am sure that it is a 260 block. Thanks for your reply.

[wired247]

I suppose if you had a 260 block on a 2 piece adapter and didnt have the cooling system dialed in right it cold be a problem that would require some attention to make it cool better.

Personally I think the guy is licking his chops after your 260 block AND selling you a rebuilt motor. The 260 block is a good thing if its dialed in right.

[tlwjkw]

Its not tha "pairing" of tha block halves. If ya have it on a two piece plate then ya need a certain type of coolin' system. If its ona one piece ya got another way ta do it and so on. If he knows Hi Perf he should know what ta look for and come up with something that will work. Tha two hole with good pump stuff cooled Bridge Ports just fine when that's all there was........jmo

Makes no difference what knida "Heinz" it is a good guy can figure it out pretty quick.....

[hunter0402]

Wired, that is really my concern as well. I just would like someone to tell me why the 260 block makes it more prone to blow up. I would hate to ignore my mechanics advice and then get the "told ya so" when i blow the thing up and it is worthless.

[tlwjkw]

Run it down ta Soddy Daisy.........

[Dave Strong]

Its not tha "pairing" of tha block halves. If ya have it on a two piece plate then ya need a certain type of coolin' system. If its ona one piece ya got another way ta do it and so on. If he knows Hi Perf he should know what ta look for and come up with something that will work. Tha two hole with good pump stuff cooled Bridge Ports just fine when that's all there was........jmo

Makes no difference what knida "Heinz" it is a good guy can figure it out pretty quick.....

BINGO, nothing like saying it the way it is.


Dave

[tlwjkw]

He informed me that the overheating issue is due to water routing on the block is different than the promax in conjunction with having a 2 hole cle lower unit that does not pick up enough water for the motor.

This is a "clue"........

[Dave Strong]

This is a "clue"........

Takes a bit of work to put a motor that is supposed to run on a one piece adapter and run it on a two piece adapter. And the other way around, but if done right it can be done.

Dave

[tlwjkw]

245/260 block. Diverters, washers, poppet. 2 piece......Ran 160/170. Purrrrrrfect! Still gettin' hammered on by a "French blood" La. boy.

[rock]

If the cle and front half are, according to your mechanic, causing heat issues, you need a new mechanic. I have ran cle lowers on 260s many times and the front half has nothing to do with cooling. What you need is a one piece plate and maybe a better mechanic. Good luck.

Rock

[TEXAS20225]

some of the trick cooling water plumbing are not good:iagree: factory plumbing on a two pc plate always works good or Merc would not have done it. I also know just a simple change to a after market impeller and water pump housing can and has caused lots of trouble especially when cutting cost corners ive been there done that :eek: never skimp on your cooling system parts always buy Merc . i wonder how he determined it was a 260 ?? only if it has certain castings and no auto oiler boss normal week end warrior wont know it from a jelly do-nut!! promax front or any gear case will not cause any sort of heating trouble!!!! its always a bummer when a unlearned buyer gets a new motor from a seller who had problems. mid 70 is 10 MPH off at least for a 225 a 260 should run low 90's i have had all of them on my Bullet

[hunter0402]

Thanks everyone for the responses. I was hoping to get a response from someone who has personally tried to do this. I know that the front half of the motor has nothing to do with cooling. The cooling issue is honestly not the problem that i am trying to address. I am wondering if anyone has ever tried to put a 260 block on a promax. The promax is a 2000 model. I know there are a few differences in the fuel management systems between the promax and the 260. Also I have been told that the bearings for the crankshaft don't match up for the 260. Thanks for the comments.

[TEXAS20225]

bearing on small bearing 260 are identical, big bearing wont work period, take some pixs!!! the issue is what then??? the 260 rotateing assembly does not know w does not know what its bolted to it will work fine fuel system Laser has to have the that front or it wont work IMHO laser is quickest on the bottom end anyway but not te top TLWJKW know all about it the pix he showed you was the same thing as you have supposedly it was to say the leas a MEAN sumbich

[hunter0402]

Well I took some pictures and can't figure out how to get them on here. If someone can tell me how to add attachments I will post them. Thanks

[JohnR]

Get a Photobucket account, load them there, then click the photo box on here while you're posting and copy the direct link from Photobucket and paste it into the box.

[hunter0402]

298824298825298826298827298828

[wired247]

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you can email me the pics at [email protected] and I can post them.

[hunter0402]

I think i was able to get them posted. Let me know if there is something that you need to see that is not in the pictures. Thanks again for all the help.

[Coupe427]

Your attachments didn't work.

It's sounding to me like the mid is from a 225 and it has a 260 power head on it. That definitely isn't a first and just needs some tinkering to straighten out the water flow. I wouldn't trade, sell or buy one of your mechanics motors until you figure out what you've actually got.

[hunter0402]

mike, i sent you an email with the photos. thank you for posting for me

[wired247]

http://imageshack.com/a/img842/7710/c4v2.jpg
http://imageshack.com/a/img845/7065/eg6p.jpg
http://imageshack.com/a/img843/1427/aryjk.jpg
http://imageshack.com/a/img834/4402/l6bmd.jpg
http://imageshack.com/a/img839/3873/ptv2.jpg

[speedinstream]

I will give you 500 $ for the time bomb there is 100% nothing wrong with that combo u have a cooling problem period u need a new mechanic he either wants yuor motor or your cash for his power head for sale.

[wired247]

Might be a early 260 block.

[hunter0402]

haha the cowl is worth $500. my water pressure is 9-10 psi at 4500 and 15 at wot. i get no overheat alarm at 30:1 mixture but if i mix closer to 50:1 i get the alarm

[tlwjkw]

24/7...Is that tha kinda number ya got on tha block ya just bought?

[hunter0402]

he told me that the easiest way to tell is that it has no mounting holes on the side of the block for the timing box. that is why the box is zip tied to the other side of the motor

[hunter0402]

thats the only number i could find on the block. i bought the motor as a package and was told it was rebuilt a year ago and only has around 40 hours on the rebuild

[tlwjkw]

haha the cowl is worth $500. my water pressure is 9-10 psi at 4500 and 15 at wot. i get no overheat alarm at 30:1 mixture but if i mix closer to 50:1 i get the alarm

How are ya getting an alarm? I can't see a sensor in tha head. Looks like tha efi sensor is in tha starboard head.......Tha temp gauge wire is cut n layin' on top of tha motor. That kinda tells me that tha gauge sensor part od tha efi thingy is actually sending signal to tha warning buzzer....Just looks like it anyway........

[6Killer]

Cast iron sleeves or nic?

[hunter0402]

i obviously don't know anymore than what i have been told lol. i was informed that since the oil injection has been removed that the only other alarm that can sound is the overheat alarm. after a long run as soon as i come off pad and start idling an alarm sounds. i immediately turn off the motor and let it cool down. after 5-10 minutes i can turn the key and the alarm does not sound

[hunter0402]

i was told they were nic but i haven't had it apart

[6Killer]

Pull a head

[wired247]

24/7...Is that tha kinda number ya got on tha block ya just bought? Its a reman number......


Nah. It just got some gibberish engraved on it.

[hunter0402]

6killer, is there a reason to need to know that information? i would rather not pull the head on the motor if it is just for curiosity.

[tlwjkw]

Can anyone tell 'bout tha adapter?

[speedinstream]

It is not early 260 block it has alternator bosses

[speedinstream]

O and I dont want the cowling just the time bomb lol

[wired247]

It is not early 260 block it has alternator bosses

Unless they bored the front it wouldn't be a late 260 block.

[speedinstream]

Looks like temp sender is being used for a guage and a buzzer not pluged into the laser harnes ecu thinks cold running rich maybee explains y down on performance

[speedinstream]

Unless they bored the front it wouldn't be a late 260 block.
Cheaper to modify front for big bearing than buy a block

[wired247]

It could just have the wrong sensor tied into the alarm as well. I'd put the port side sensor back on the port side and install the starboard sensor where its supposed to be and plug everything into what its supposed to be plugged into. He might just be getting an alarm when the motor is at operating temp and the ECU is making it run rich all the time. .

[Onetime]

Looks like a factory replacement block. 99 year model. Probably is a 260 because it has the alternator bosses but are not machined. Had a few of these and that's the way they came. As some say on here it's a frakenmerc. Somebody made the 225 front half work.

I'd look deeper into the warning horn circuit because if there are no sensors what's setting it off. Appears that there is no water separator that the 225 would normally have. That's another source for the warning horn.

Really tough figuring these thing out from a message board!

[speedinstream]

It could just have the wrong sensor tied into the alarm as well. I'd put the port side sensor back on the port side and install the starboard sensor where its supposed to be and plug everything into what its supposed to be plugged into. He might just be getting an alarm when the motor is at operating temp and the ECU is making it run rich all the time. .exact what I was thinking

[tlwjkw]

6killer, is there a reason to need to know that information? i would rather not pull the head on the motor if it is just for curiosity.

In your deal it ain't just curiosity!!!

[Onetime]

Just looked at the pictures again and saw the water separator. Looks like the wire is attached to the bottom of the separator so it could be causing an alarm. Does it have the sensor/alarm control box?

[hunter0402]

Thanks to everyone who has commented. Im gathering that if done properly the setup that i have should work fine as long as someone who knows what they are doing has set it up. I will take it to another mechanic and try to get to the bottom of the overheating problem, if there is one. On the subject of performance i have ran rich and lean and there is no difference in performance. I am running a 24p trophy and have not tried a 26 which i know is what should be on there. I haven't tried it yet because the guy i bought it from told me that he tried a 26 and the motor wouldn't turn it. wouldn't ever get it out of the hole. my mechanic told me that was because the promax front is not giving the 260 block enough fuel and is basically starving it. any insight on this?

[hunter0402]

where would the sensor/alarm be?

[Onetime]

Just read some of your posts again. So if you run the oil mix at 35:1 no alarms go off but at 50:1 the alarm goes off?? Don't see how the oil ratio would change operating temperature. 35:1 and 50:1 are your oil mix ratio and are not changing the air/fuel ratio that the computer is controlling. Is it a steady tone or intermittent when the alarm goes off?

[hunter0402]

it is a steady tone and the last time it happened i trimmed the motor all the way up and there was steam coming out somewhere

[wired247]

Thanks to everyone who has commented. Im gathering that if done properly the setup that i have should work fine as long as someone who knows what they are doing has set it up. I will take it to another mechanic and try to get to the bottom of the overheating problem, if there is one. On the subject of performance i have ran rich and lean and there is no difference in performance. I am running a 24p trophy and have not tried a 26 which i know is what should be on there. I haven't tried it yet because the guy i bought it from told me that he tried a 26 and the motor wouldn't turn it. wouldn't ever get it out of the hole. my mechanic told me that was because the promax front is not giving the 260 block enough fuel and is basically starving it. any insight on this?

Find another mechanic. The promax front uses the same reeds and has the same dimensions as the 260 front half. The air intake is different but the motor doesnt really care until higher RPM's. As was mentioned earlier you'll get better low speed air mixing with the promax laser air intake with the 260 horned front taking more air in on the top end. Top end meaning over 7500 or so. Cutting fishing motor blocks to 260 port specs is a somewhat common mod.

When you say you've run it lean and rich what do you mean? Theres no simple adjustment to be able to do that. The ECU controls that from sensor input and your sensors do not appear to be configured correctly.

You should be able to buzz a 26 pitch to the moon with that setup.

[tlwjkw]

How are ya getting an alarm? I can't see a sensor in tha head. Looks like tha efi sensor is in tha starboard head.......Tha temp gauge wire is cut n layin' on top of tha motor. That kinda tells me that tha gauge sensor part of tha efi thingy is actually sending signal to tha warning buzzer....Just looks like it anyway........

You need ta address this by doin' whats been suggested above. Oil mix ain't gonna alarm. Ya gotta know which adapter ya got in order ta make tha coolin' stuff work right whether its nic or steel...........Till ya get all that figured out anything suggested here is just a fart in tha wind and ya might just "burn it to tha ground"...........

BTW. Take that zip tied box off and "float test" it.........Reset max timin' at 23*

[6Killer]

If you pull a head, you bypass all the guessing and bull$hit.....

Figure out what you really have then move forward from there.

[TEXAS20225]

its the wiring! no hot horn sender give me 15 minutes with it no boxs, no problems only smiles, front has been modified for big bearing stuff its a good mota:cheers:

[Onetime]

Is that why it's down on power also?

[speedinstream]

Yes ecu thinks cold running very rich

[tlwjkw]

Even if tha efi sensor is on tha stbd side it will still read a temp as for as tha ecu goes. All tha tan wire in tha efi sensor is for is a temp gauge. Don't think it has anything ta do with what temp ecu sees..............

[patchesII]

Find a good mechanic that knows what he's doing. Paul Nichols in Soddy Daisy could help you if you can't find one around that's familiar with high performance Mercury's. As Sixkiller said, the sleeve material could answer your question. Paul could do everything for you

[tlwjkw]

Plus one! Won't try ta beat ya outta your **** either.............

[speedinstream]

Even if tha efi sensor is on tha stbd side it will still read a temp as for as tha ecu goes. All tha tan wire in tha efi sensor is for is a temp gauge. Don't think it has anything ta do with what temp ecu sees..............either side will work I guess but thete are three wires unplug them and motor goes very rich that is how the ecu knows when motor is up to opp temp

[tlwjkw]

That only uses tha two wires. Tha third (tan) is just for a temp gauge. Makes no difference if its plugged in to anything or not. On tha original Laser efi tha sensor only had two wires. There was an "optional" at extra cost three wire to be able ta use a temp gauge. Tha three wire finally got ta be a "standard" issue after a coupla years...........

[R.grover]

Like others have said take it to another company to look at it. Drop the name on here of who you are looking at using to see if they are any good as like any thing just because you have a mercury banner on ya shop don't mean u any good.