1989 Mercury XR4 Black Max 150 Upgrade Capabilities

[wired247]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

If its a Xr4 its a carb engine, if fuel injected the only way to fatten it up is to buy a adjustable ECU...

4 blades are slower than a 3 blade but handle better and add a little more lift to transom..sti;; need to know if you have small or big gearcase and pitch of old/new prop...

Depends on the prop model, maker, slip, etc. Even among makers you'll find a huge difference in prop performance on different makes with the same pitch. The one I cited is rated at 21 pitch even though its probably actually a 23-24 pitch prop unless it actually does generate negative slip numbers which is unlikely. If he wants to go 65 MPH with a 2:1 or higher lower in the 6000-6300 range its a good choice.

 

[skeletor6]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

If its a Xr4 its a carb engine, if fuel injected the only way to fatten it up is to buy a adjustable ECU...

4 blades are slower than a 3 blade but handle better and add a little more lift to transom..sti;; need to know if you have small or big gearcase and pitch of old/new prop...

I apologize. I meant oil injected. This motor is NOT fuel injected. Furthermore, how do I tell if I have a large or small gearcase? Do I have to get the serial number off my motor and research off of that?

Also, there are no identifiers on the prop that is on it. And there is damage to one of the blades. It looks like midway through it hit something. The damage is not large, but nonetheless it appears I need a new prop. So suggestions on where to start the "trial and error" process would be greatly appreciated. If that is dependent on the gearcase, then the latter needs to be answered.

Thank you all for your help!

 

[wired247]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

On the prop you will have people telling you a lot of things about props. Some will be true based on what they have read or tried. Some will not be as true depending on the brand or model. 3 bade props may or may not be faster than 4 blade depending on brand or model. Pitch numbers also can be apples and oranges from manufacturer to manufacturer. One manufacturer may have a 3 blade 21 pitch prop that gets blown out of the water by another manufacturers 4 blade 21 inch prop or vise-versa or even within the same manufacturer. A lot is going to depend on your motor mounting height too. Best thing you can do is look for someone with a similar hull and motor and ask what they feel has worked for them and use that as a starting point. I have a similar hull with a similar motor and have tried 15 or so props on mine. Some work well and others not so well. Youve got to put a prop on it whatever it is. If its a 150 you probably have a small gearcase and will use a 14 inch ish 4 1/4" case prop. small props will go on large gearcase just fine

 

[skeletor6]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

Hey All,

So I finally got to the bottom of things. I took the boat to a licensed boat mechanic. He could tell just from starting it that something was wrong with the motor. Said he has fixed many of these motors in his day. He could not tell the extent of the repair until he got into it. Well here's what it looked like on the inside...







Anyways, the mechanic says three pistons and rods are bad. The crank is junk and the block is junk. It also has been rebuilt before and rather poorly in his opinion. He is in the process of rebuilding it and has acquired all of the parts. He says that when it is done it will be a 200hp motor. I have read threads saying that it is possible to turn the Merc 150 XR4's 2.4L into 200hp, but does this sound about right to you guys?

Thanks for all the help.

 

[skeletor6]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

One more pic

 

[wired247]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

You cannot turn a 150 into a 200. You'd need a 200HP block, 200 HP carbs and a 200 HP reed block set. Basically, in your case you with your bad everything else you would need a 200 hp donor long block. The 150 HP block cab be resleeved at around $300 a hole for the bad bores and salvaged but with everything else, especially the crank and rods being shot, I dont see how this is going to be a cost effective rebuild unless you are starting with a donor powerhead.

150 and 200 blocks have intake and exhaust ports in different places. Even XR4 blocks. You might get into the 160-175 range if the heads get shaved but without some serious port work and exhaust chest work you arent going to get 200, Be wary of any builder who tells you he is going to get you 50 HP without some major mods.

 

[skeletor6]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

You cannot turn a 150 into a 200. You'd need a 200HP block, 200 HP carbs and a 200 HP reed block set. Basically, in your case you with your bad everything else you would need a 200 hp donor long block. The 150 HP block cab be resleeved at around $300 a hole for the bad bores and salvaged but with everything else, especially the crank and rods being shot, I dont see how this is going to be a cost effective rebuild unless you are starting with a donor powerhead.

150 and 200 blocks have intake and exhaust ports in different places. Even XR4 blocks. You might get into the 160-175 range if the heads get shaved but without some serious port work and exhaust chest work you arent going to get 200, Be wary of any builder who tells you he is going to get you 50 HP without some major mods.

That is exactly what he did. He said the block and crank were junk and also 3 rods and pistons. Since so much was shot in my motor he got a donor to use the parts off. The block rods and pistons off the donor all looked good. The donor he got for a good deal and had it shipped up from Florida.

I am not entirely sure I gave the exact year of my motor because there is no need for them to be resleeved because they are not chrome lined. That was something he was worried about when breaking it down because he said he would have to send them off to be sleeved and that would drive the cost up big time.

The rebuild is certainly costly, but it is being done off of used parts and it was kind of a crap shoot that the donor motor turned out good for parts. The guy has fixed about 5 different watercraft motors throughout a span of 8 years with my best friends family. So he's about as trustworthy as I will get.

Also, wanted to add that the motor is no longer Oil Injected and will require a 40:1 mix. In addition to the parts on the donor was a crank and new bearings and gaskets.

Still want a second opinion and appreciate your input!

 

[wired247]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

In that case you arent really turning a 150 into a 200. You are turning a 200 into a 200.

BTW steel bore blocks get resleeved too. Ive got one down at LA sleeve getting done right now. They bore the block oversize and press in a complete sleeve. Nicosil blocks get a whole different process.

Unless you are planning to live at over 6000 RPM you won't need to run 40:1. 50:1 is sufficient and standard. More oil won't hurt but it wont help either.

 

[skeletor6]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

Yes you are right. That is a more accurate description. I am basically going off of the descriptions that I am told. I am not in tune with how exactly he is breaking it down, fixing it, etc. Exactly why I appreciate the information you are giving me.

Regarding the sleeving, is that a process that has to be sent off to be done as you described with yours. Or is it feasible that it can be done at someones own shop? He said the the Nicosil sleeving process had to be sent off to be done, but he would not have to send them off to be done if they were steel.

Thank you for your input and information. I do not plan on running it really hard, just sporadically to test it out. Mostly will be getting me from spot to spot while fishing and/or cruising. Is there a break-in process for when these motors are rebuilt? Also, performance wise, am I going to encounter any problems running this on my 1986 Stratos 179v rated for 150hp? Thank you for your help.

 

[wired247]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

Nah. You'll be fine. You'll only end up pushing the boat as hard as it and you can stand. Not a huge difference between a strong 150 and a run of the mill 200 anyway. You'll have more top end and mid range power but the bottom end will be a little softer.

Any good machine shop can install a sleeve. Its the port work that gets a little tricky but with pre cut ports its not a huge deal.

For a full rebuild you'll want to take it easy and not run much over 4000-5000 rpm for a dozen hours or so. Vary the RPM quite a bit . Its more important to baby a new lower than a new powerhead.

 

[skeletor6]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

Nah. You'll be fine. You'll only end up pushing the boat as hard as it and you can stand. Not a huge difference between a strong 150 and a run of the mill 200 anyway. You'll have more top end and mid range power but the bottom end will be a little softer.

Any good machine shop can install a sleeve. Its the port work that gets a little tricky but with pre cut ports its not a huge deal.

For a full rebuild you'll want to take it easy and not run much over 4000-5000 rpm for a dozen hours or so. Vary the RPM quite a bit . Its more important to baby a new lower than a new powerhead.

Thank you for the advice. I will run with it. I have also read there will not be a huge difference in the 200hp vs the 150hp version. Nonetheless, being an old motor and boat I just hope it can be reliable. Have you had a chance to run yours? What kind of top-ends do these produce on average? I am hoping I can get somewhere around 60.

 

[wired247]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

I currently have a somewhat modified 1996 2 liter fat block 150. 21 pitch 4 blade on a 2:1 lower. 17 foot 1981 checkmate enticer. It will do 64 with that prop but to be honest that boat is absolutely no fun to drive over 60 with that motor. I have to get the front end up too much and it walks all over the place. I've had a 2.5 260 and a 3.0 225 merc on the same boat and with the bow down low it would plow through to 75 MPH.

You can easily do 60 MPH with the right prop or even the wrong prop on your boat. You'll do mid to high sixties without too much trouble. a mile or two faster with the right prop and a jackplate.

 

[skeletor6]

Re: 1989 Mercury XR4 Black Max 150 Upgrade Capabilities

I currently have a somewhat modified 1996 2 liter fat block 150. 21 pitch 4 blade on a 2:1 lower. 17 foot 1981 checkmate enticer. It will do 64 with that prop but to be honest that boat is absolutely no fun to drive over 60 with that motor. I have to get the front end up too much and it walks all over the place. I've had a 2.5 260 and a 3.0 225 merc on the same boat and with the bow down low it would plow through to 75 MPH.

You can easily do 60 MPH with the right prop or even the wrong prop on your boat. You'll do mid to high sixties without too much trouble. a mile or two faster with the right prop and a jackplate.

That is an excellent setup! I would love to take a ride in a boat going 75mph.

UPDATE: 7/26

I now have the motor in use. It was rebuilt with a donor motor and it is now a 200hp 2.4L Mercury V6. The boat, on a beat up 4 blade 24 pitch prop goes 62mph on the gps.

Here are some issues that I still have with the motor that the mechanic discussed with me. The carbs need some work and they may even be the wrong carbs. He said he still has the 150hp carburetor and that it also could use some work on that carburetor. Also he mentioned maintenance and cleaning on some other part as far as tuning it up. I believe he meant cleaning it and what not. I was wondering if someone could shed some light on that?

Also, the mechanic said I have a small gearcase on this motor. He was mentioning that with this gearcase that it has a smaller diameter where the prop goes on, so it takes a special sized prop (which is hard to find) to get it going. He said that he wanted to buy a large gearcase and trade it for the one on my motor. That way I could get a prop easier and if I wanted a nice stainless steel prop I could get one. He mentioned it had something to do with the diameter. I am a little confused about the situation, I feel like he just wants my gearcase because he said there will not be any performance difference with switching the gearcase. From you guys who know a thing or to (unlike me) is that situation even logical?

Furthermore, we put a 23 pitch stainless steel prop on there and it was able to max out at about 5800 rpms at top speed. I did not have a gps out at the time to tell how fast I was going. The mechanic mentioned that it spun a lot more. I noticed that the difference between that prop and the prop I am using is substantial. Right now, my boat jumps really high on accelleration and takes more time to plane out than did the 23 pitch stainless steel 3 blade prop that he put on to test it out when I was with him.

The prop I have on there now (4 blade 24 pitch dinged up) maxes out at about 5000-5200 RPM's at top speed. I have the jack plate up really high and trip the motor up high as well as the boat planes out. I can noticeably here the RPM's rev higher as the motor is trimmed up more.

Just a simple question on taking off. How should I have the motor trimmed? I was told about 1 to 2 inches below parallel. Is this correct? I do not like how the boat is taking off at the moment and I want to make sure that it is not due to user error.

Thank you all for all of the help that has been previously given to me and any input on my current situation is greatly appreciated!

 

[mack4k]

I know this is quite a few years old...I have the same small gearcase and am having problems finding a prop to fit it. Were you able to find one you liked? My question doesn't involve diameter / pitch so much just literally to fit the gearcase? Thanks

 

[jbcurt00]

@mack4k Skeletor hasnt been on in nearly 5yrs.

Not likely to get or reply to your post, hence the 90day inactive guideline

Start a topic about your prop hunt over in the prop forum