hustler57 Posted September 7, 2006 Share Posted September 7, 2006 hey fellow As some of you may known i have been in the process of getting my old 140hp johnson rebuilt and i finally got the block of to discover that the boat mechanic tells me that i need new cranks conrods bearings pistons re bore the cylinders at a cost of at least $4500.. and i simply dont have that sort of money on me.. what to do what to do ???? i can either try to find another cheap motor around the $1200 or spend about $800 just getting new pistons and re boreing the cylinders out ???? help i cant decide. and if i only just do that i dont know how long it will last ??? fellow does any 1 know how much and or know some 1 who is selling a old boat motor so i can get out on the water ???? oh and its to go on the back of a 5.7m cruise craft hustler help needed Link to comment Share on other sites More sharing options...
Grantm Posted September 7, 2006 Share Posted September 7, 2006 Geez ! Question is does all this work need to be done because the repairer has to give a warranty, or because it REALLY needs to be done ? You probably find that half that stuff would be ok - just not perfect. Unless there was something drastically wrong with the parts mentioned I personally would rebuild it with new rings and see how it went ! There tough old motors and if your budget is tight it may be an option. Can you post some pics or give a detailed description as to why these pistons and crankshaft need replacing ? I understand that repairers need to build it to a warrantable level and most wont do anything half hearted, but thats not nessesarily what it needs to go around again. If you cant spend the dollars it maybe able to be rebuilt without the need of even a rebore. Why does it need a rebore ? Lets have a look at exactly WHY all this stuff needs doing. Could be some shortcuts perhaps. Link to comment Share on other sites More sharing options...
pjbink Posted September 7, 2006 Share Posted September 7, 2006 If the crank and bearings need replacing then there is no point leaving them in place and rebuilding the rest of the engine. What will happen is that the worn crank and bearings will create excess movement and quickly destroy the pistons, cylinders and who knows what else! The crank is the really expensive part (probably worth 2-3 K). One option is to get it rebuilt. A properly rebuilt one to engineering tolerances will be as good as new and will cost a lot less, but it is hard to find a place with the necessary expertise. If you are really lucky someone might have an exchange re-built one one the shelf. If it is an old motor you might be better off scrapping it and buying a second hand one with a warranty. You would still have to spend $4,500 and probably a few thousand more to get a decent motor. Link to comment Share on other sites More sharing options...
netic Posted September 7, 2006 Share Posted September 7, 2006 HI Mate, i had a similar problem with one of my motors a couple of years back. I decided to scrap the current motor and sold it for parts on ebay for $300, then bought a 90's model 115 hp yammi for $3900 which ran perfect Link to comment Share on other sites More sharing options...
hustler57 Posted September 7, 2006 Author Share Posted September 7, 2006 ok thanks a lot guys for the advice i need all the advice i can get. im getting another guy to look at it on saturday to see what he thinks and the reason why i started to rebulid it is because one of the cylinders had no compression and that as because of the piston damaged the cylinder and so i had to re bore all 4 cylinders and put in oversized pistons. (that was the idea anyway) . i understand that its an old motor and has to have wear and tear but it was going ok before it loss compresion which means the pistons is gone. the old johnsons are as hard and reliable as a old bull and thats why i deided to go with that motor. when this happened i was out on botany bay and with no compression in 1 cylinder and just 3 cylinders going i still was able to get back from the heads back to lurgarno boat ramp. while im still unsure what to do . il have a better idea tomorrow after another guy looks at it for me. id love to be able to afford a good used motor bor around $5000 but i spent all my money when i bought this boat and my catamaran (both at the same time) i paid $9k for tthe boat which is insured for $18k . so im on a really tight budget. Link to comment Share on other sites More sharing options...
hustler57 Posted September 7, 2006 Author Share Posted September 7, 2006 hey grantm hmmm you make a interesting point. im no mechanic myself but i guess that mechanics do work for them selves and the more they do the more they make. and i guess since that it was going ok before this happened. just simply reboreing and oversized pistons may hopefully get me a couple of years out of it. im aware that its an old motor and not in perfect condition but im not expecting another 10 yearss out of it. and if its just in ok condition then il simple rebore and oversize pistons in it. which has to be done anyway. if i had the money to spend on making everything in it perfect i would of got a new motor but i dont and i just want it to be ok not perfect. Link to comment Share on other sites More sharing options...
Grantm Posted September 8, 2006 Share Posted September 8, 2006 hey grantm hmmm you make a interesting point. im no mechanic myself but i guess that mechanics do work for them selves and the more they do the more they make. and i guess since that it was going ok before this happened. just simply reboreing and oversized pistons may hopefully get me a couple of years out of it. im aware that its an old motor and not in perfect condition but im not expecting another 10 yearss out of it. and if its just in ok condition then il simple rebore and oversize pistons in it. which has to be done anyway. if i had the money to spend on making everything in it perfect i would of got a new motor but i dont and i just want it to be ok not perfect. Being a mechanic (not hands on anymore though) I can tell you that does happen. Not specifically to make more money but because your reputation is on the line and you have to warranty any work. A lot of people dont need to have their motor rebuilt to 'perfection' and can simply have a lesser rebuild done and like you say get a few more years out of it. It is possible (not probable) that your motor just needs 1 new piston and a hone ( depending on the actual damage ) What does it need a crank for ? I know this is not the best way to build an outboard obviously, but im just trying to offer some suggestions that will cost stuff all and get the motor running albeilt for a limited time. Not all motors have to be built to perfection to run again. If you pulled apart an engine that was running fine but with 2000hrs on it you would never think it would run based on how it looks inside - but they do. Problem is mate your unlikey to find a retail repairer willing to take any chances due to liabilty. Link to comment Share on other sites More sharing options...
hustler57 Posted September 8, 2006 Author Share Posted September 8, 2006 thanks for the advice mate il let you know how i go 2morrow.. i found some one who has a 1992 140hp johnson V4 for sale and he is asking $2500 for it. a met of mine and myslelf are taking it out tomorrow for a short run on botany bay. if the motor rounds great and sounds ok and my old one has had it il buy this one and borrow some money of a friend and if my old boy isnt as bad as what ive been told then il just rebore and oversize pistons . thanks for the inside help from a ex mechanic mate i really appreciate the advice. il let you know how i go 2morrow. Link to comment Share on other sites More sharing options...
Flightmanager Posted September 8, 2006 Share Posted September 8, 2006 If possible , when you check out this motor , run a compression check. Also , grab hold of the flywheel , and check for lateral play. The condition of the plugs ( colour , deposits ) can also give you a hint as to what is happening in the top end of the motor . Check the general condition , particularly for corrosion around the transom mount . Check the oil in the lower leg , also for any signs of leaks around the heads . Have a close look at the propellor shaft , and ensure that it runs true . You probably know all this stuff already , but this is what I would be looking at . Ross Link to comment Share on other sites More sharing options...
tafc010 Posted September 9, 2006 Share Posted September 9, 2006 Wow, does a crank really cost 2-3K, I would find it hard to justify that sort of price. What is so special about a marine crankshaft? I assume they are nitrided and internally balanced? What material are they made of? Are they forged, Billet or just a cast nodular iron? I'm interested now because I know what I pay for cranks for my race car and I KNOW the stress we put them through is far more that a marine outboard. Anyway just wondering.CYA Geoff Link to comment Share on other sites More sharing options...
pjbink Posted September 9, 2006 Share Posted September 9, 2006 Wow, does a crank really cost 2-3K, I would find it hard to justify that sort of price. What is so special about a marine crankshaft? I assume they are nitrided and internally balanced? What material are they made of? Are they forged, Billet or just a cast nodular iron? I'm interested now because I know what I pay for cranks for my race car and I KNOW the stress we put them through is far more that a marine outboard. Anyway just wondering.CYA Geoff Geoff, Why do they cost so much? Well anything with the word 'marine' or 'outboard' in front of it tends to cost a lot! Ie for whatever reason outboard parts cost a lot more than automotive parts. One thing your race engines don't have to put up with is saltwater. This is what usually stuffs up a crank, saltwater getting in through a seal or gasket. Once it gets in to the bearings and sleeves the fine tolerences are destroyed by rust and the excess movement will just get worse and eventually destroy the whole engine. Also I think marine engines get a much harder life than automotive engines. A car is coasting most of the time whereas a marine engine is constantly under heavy load to push the boat through the water. Also the revs are a lot higher (at least with the 2 strokes). When you are cruising in a boat you are usually doing 4000-4500 rpm. My car doesn't do more than 2,500 rpm on the freeway. PS I don't know the details regarding construction and materials in outbard cranks. I had one rebuild on my motor so thats were my knowledge comes from. Link to comment Share on other sites More sharing options...
pirate pete Posted September 9, 2006 Share Posted September 9, 2006 I have a 1984 J140TLCR 140hp Johno. I have had it since new on the back of the Haines. Last year I had a partial rebuild. I dropped rings in 1 cylynder and scored the bore quite bad. I pulled the power head off and a mate did the work. It would not hone out so he had 1 cylinder bored 1 oversized piston and rings new rings for the other 3 cylinders, bearings, new waterpump housing & impeller,Gaskets, fuel pump, Thermostats totaled out at $1600.00. The old girl is going as good as the day I got her. In April I had her up a Nelsons Bay for the Trailer Boat Comp 95 klms in 1 day did not miss a beat. Pete Link to comment Share on other sites More sharing options...
tafc010 Posted September 10, 2006 Share Posted September 10, 2006 Billfisher, Thanks for that, I honestly believe that there is no reason why a marine crank should cost that much. My engines see 9500 rpm to 11500 rpm, certainly in short bursts and with Alcohol for fuel oil dilution is extreme, as are the engine temps etc. There should be no reason for a crank to fail in any application if it has oil, the right balance and the right clearances. My mind was just wandering a little. We pay about $4500 for a crank that is a custom billet work of art, and gives us about 20 1/4 mile runs before needing to be binned. I think the statement about marine and jacking up the price seem to go hand in hand. We often see regular Chev V8 components cheap as chips but when you cross reference them through Mercruiser the price quadruples. Their trick is no warranty if it's not Mercruiser, even though GM made both parts with two different part numbers on them. Anyways Have a fun day. CYA Geoff Link to comment Share on other sites More sharing options...
harold Posted September 12, 2006 Share Posted September 12, 2006 the only additional advice i can offer is to check the back of the Trade A Boat magazine, they have all sorts of stuff for sale and many marine engineers advertise their services. Might be a waste of time but you just never know. Link to comment Share on other sites More sharing options...
hustler57 Posted September 12, 2006 Author Share Posted September 12, 2006 hey fellow just as update. ive bought a second hand 140hp and im picking it up next wednesday and putting it on the boat. i got it for$2.5k and it seems to go great and very well looked after Link to comment Share on other sites More sharing options...
Guest danielinbyron Posted September 12, 2006 Share Posted September 12, 2006 hey fellow just as update. ive bought a second hand 140hp and im picking it up next wednesday and putting it on the boat. i got it for$2.5k and it seems to go great and very well looked after and you kept one for spares or trading it in... anyway alls well that ends well... well done son Link to comment Share on other sites More sharing options...
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