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'84 150 HP Issues

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scottyj1011

New member
Hi all,

First time poster here and sorry if something like this has already been asked and answered. I'm looking at buying a bass boat that has an '84 150 HP Johnson. The boat is in great shape but the owner says the piston rings broke in at least one cylinder. I'm not real great with motors so my questions ares 1) Is this repairable or are we looking at a complete rebuild, 2) If repairable, is it something a novice could handle without to many special tools or with the help of some car mechanic friends, and 3) If it needs a rebuild, is it even worth it? The boat itself is a 15 foot 1983 Skeeter with the trailer and a MinnKota trolling motor for $450. I'm leaning towards worth it even if I have to rebuild but other advice I've received is the opposite. Any insight into how much trouble this motor will be is greatly appreciated.

Thanks in advance!
 
You might be able to jus replace the rings but doing it you will have to take the whole motor apart. its hard to do but if you take your time and buy a manual you might be able to do it. ive rebuilt smaller outboards and its not that difficult. I think the best thing to do is look for a used motor to put on it. 450 isn't that bad if the transom and floor are in good shape. In my area you can get motors for around 700 to 1200.
 
The entire motors condition has to be evaluated first. Lower unit, trim/tilt, controls, overall appearance, has it been worked on before? Compression test, very critical, spark test, condition of wiring, etc..... Then determine what caused the ring failure, loss of lube, overheating, yes check for discoloration on paint on heads and exhaust cover. Then you are ready to remove head and check damaged cylinder. If it needs boring.....and it likely does, then you will have a huge expense. In order to keep things in balance and syncronicity, you must bore all cylinders.....machine work is high and many shops are poor at small engines. You need to find a great shop that will set you up with proper clearances and cylinder bore finish. This is meticulous work, you will have to go to study before you attack it. take lots of photos with your phone as you dismantle to get parts and wiring back to their original position. It will be gratifying to fix it yourself.
Another option is to go with a used powerhead. Avoid salties and check here in Minnesota, up by Detroit lakes are some great outboard "boneyards". Be sure you get a leakdown and/or compression test results that were done before the powerhead was pulled off. Get a complete gasket set with the motor and be sure to change crankshaft seals and head gaskets. Face heads and block with 220 or 240 and a nice flat piece of iron or hardwood, using mixed gas or WD40 as lube agent while surfacing. Be sure to be careful while scraping any aluminum surfaces, don't harm them. Clean all bolts with wire wheel and lite anti seize threads and top of head bolts where they face against head surface, torque in proper sequence in small intervals until you meet required specs. Everything can be found on line if you look hard enough. You will need to buy, borrow, or rent a torque wrench to cover the torque ranges involved. This will mean an inch pound as well as a foot pound wrench. With experience you can forgo the inch pound wrench as long as the foot pound can get down to the 20 range.
Still interested?
I do have a crank and set of std pistons for this motor, sold the block, however, last year on e-bay.
 
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Hey folks,

Thanks for the input on this. I've decided to pass on the boat (before Tim's post but if i was on the fence still when I read it, I would have come to the same conclusion). I appreciate the insight. There were just to many uncertainties about this. After talking with the seller, he's never taken it on the water or anything. Don't feel like buying a small money pit on a hope and prayer.
 
Okay, remember before buying any motor, hear it run, check compression and spark, then check lower unit lube. This will make your life easier. I buy junkers all the time, but still evaluate the motors viability and potential as even parts.
 
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