Engine Rebuild On My Boat!

[lkn4bss]

Been having a idling problem with my engine (Johnson 40). Took it today and had it checked out. The top cylinder has low compression and a scoured cylinder. Going to be 1500 - 2k to build it. Should've had a compression check before I bought It.

[BKeith]

I'm not sure who you got the quote from but that is one outrageous price for a two cylinder motor, even if the motor needed a new sleeve, parts and labor should not be more than $1,000. If you can rebuild a auto engine, you can build a two stroke with a little good guidance and it would be around $500.

[lkn4bss]

That price includes removing the oil injection system and putting a regular fuel pump on. Also new waterpump and carb rebuild.

[BKeith]

Still outrageous. Fuel pump without oil injection is approx $165. Water pump is about $45, carb kits about $15. A little geewizz info, you don't have to replace the fuel pump to do away with the oil injection. All you have to do is uplug the 4/5 pin connector (depends on year model) so the alarm doesn't sound. Everything else can stay and it won't hurt a thing. If you want to take the oil tank out of the boat for the extra room, you can do that also. You can leave the oil hose or take it out. If someone tells you the pump has to be replaced, and you can't just quit using it by unplugging the connector, they are blowing smoke. There are thousands of them that's been running for years with just unplugging the connector.

The extra labor for doing the carbs and water pump is ony about 1 1/2 hours and there is no extra labor for replacing the fuel pump because it's already off and it takes about two minutes to take the mounting bracket off the old one and install it on the new one

[lkn4bss]

It's a 95 Johnson 40. Was told the VRO pump had to come off and a regular diaphram pump had to be installed. I looked up the parts on marineengines.com

.030 Wiseco pistons with rings and pins

rod bearings

wristpin bearings

front crank bearing and seals

middle crank bearings

rear crank bearings and seals

gasket kit

Machine work

total of 600.00 for powerpack and no labor added

Carb kits

primer block,valve and gasket (Mine leaks when choked)

Fuel pump

Roller and sleeve's

total for fuel system 210.00

Water pump kit 58.00 (probably don't need it. better be safe than sorry)

so 900.00 with shipping for just parts.

guy said 600.00 labor

1500.00 total +/-

All parts are OMC but pistons.

I could rebuild it myself with no doubt. My problem would be setting all the linkages and setting the timing, adjusting the carbs correctly.

[BKeith]

Ok, a little more geewizz info. The only bearing that normally needs replacing is the bottom main. It's extremely rare for any of the other to need replacing. These are not like your car motors, the needle bearings last an extremely long time. The only time I replace one is if it's blue, showing signs of extreme heat or is pitting and both of these conditions are extremely rare. You always replace the lower main because it's a roller bearing and is the one that keeps the crank from walking up and down. You will find that even some of the best engine builders in the country feel the same way.

The only time all the bearings are replaced is when it's classified as a Remaned power head, and that's where some take advantage of you because the sell them as Remaned but they are really just rebuilt. I've seen some crooks that replace the rings and gaskets and call it remaned.

Bore it, install the new pistons, gaskets, seals and lower main bearing. Those are the only parts you noramlly need in the power head. Everything else is usually just useless money spent. You can buy an aftermarket full gasket set almost as cheap as BRP sells just the head gasket.

The carbs are easy enough to build and setup. However with that said, I have a set I rebuilt twice and they still didn't work so I bought another set, rebuilt them and they worked fine.

Timing and all that other stuff is a piece of cake with a little guidance to help you understand what you are doing.

The primer solenoid, you can get just the top section for about $20.

One word of caution, do not have the block bored at the standard machine shop, unless you know how to chamfer the edges of the ports. If the ports are not chamfered, the sharp edge can grab a ring and break it.

[lkn4bss]

Thanks for all your help. The guy gave me a parts list. It only had rod and wrist pin bearings. I added the rest myself do to my automotive background. Guess I should tear it down to see what I really need.

[RobertBG]

Those numbers anyway you look at them are tough to swallow on a 40hp.I'd pull the head and see what is really going on inside,chances are you might be able to run a bead hone through it clean re ring and assemble it all and have a good running motor.I've scene many stuck rings on motors that sat give bad cr readings.

How bad was the compression?Before spending that kind of money I'd check into it myself...........whether I fix it myself or not i would deffinitely CONFIRM any diagnosis with that type of price tag

[lkn4bss]

Here is a pic of the cylinder. They are some grooves and metal transfer. It needs boring and pistons.

[BKeith]

Looks like it might have been run hot, or oil starved. If oil starved, you might find a whole lot more damage when torn down. Many times it takes out the crank.

A few more words of wisdom that will save you a bunch of money. It's very common and an acceptable practice to only bore and replace one piston if the other sleeve is good.

Also, you might be surpised at how good that sleeve will clean up. You can easily take it .005 over size and still work just fine. Anything more than that will give you a piston skirt tick when cold. I've seen some mighty ugly sleeve clean up to like new with a little bit of honing. Now, I'm talking about a real cylinder hone, like a Sunnen, not one of those three fingered glaze buster of ball hones. Being a blind hole, you have to be very cautious about making it a tappered hole.

If you think you can do it yourself, you should easily be able to do everything for less than $500, if the crank is good. If interested, I can give you my cell phone number and talk you through the whole process and all the do and don'ts. If you can build a car engine, you can build an outboard, but there are some things you need to know that are unique and you can end up with a big, high dollar piece of scrap metal if you do it wrong. I'm actually not that far from you but I don't build engines for other people.

[RobertBG]

Looks like it might have been run hot, or oil starved. If oil starved, you might find a whole lot more damage when torn down. Many times it takes out the crank.

A few more words of wisdom that will save you a bunch of money. It's very common and an acceptable practice to only bore and replace one piston if the other sleeve is good.

Also, you might be surpised at how good that sleeve will clean up. You can easily take it .005 over size and still work just fine. Anything more than that will give you a piston skirt tick when cold. I've seen some mighty ugly sleeve clean up to like new with a little bit of honing. Now, I'm talking about a real cylinder hone, like a Sunnen, not one of those three fingered glaze buster of ball hones. Being a blind hole, you have to be very cautious about making it a tappered hole.

If you think you can do it yourself, you should easily be able to do everything for less than $500, if the crank is good. If interested, I can give you my cell phone number and talk you through the whole process and all the do and don'ts. If you can build a car engine, you can build an outboard, but there are some things you need to know that are unique and you can end up with a big, high dollar piece of scrap metal if you do it wrong. I'm actually not that far from you but I don't build engines for other people.

good advice, while 99% of my 2 stroke knowledge comes from racing 2 stroke bikes.I wouldn't be surprised either if that cylinder went lean although i didnt notice any signs of detonation.I too think there is a good chance it'll clean up to usable specs as you'll find most of the damage is from the piston left on the cylinder wall.I once finished a race after cleaning a jug for my kdx that was worse then this,and used it for a practice motor long after.

[lkn4bss]

I think it was run lean. I have rebuilt and built performance automotive engine also a few 2 stroke dirt bike and 4 wheeler engine too. I will tear this one down and inspect it. I have a friend who owns a machine shop with a good Sunnen hone. Will see if 0.005 will clear it up.

BKeith, any help would be greatful! pm me your #. Are you close enough to look at the parts?