Thinking of buying this boat with an 85 hp Johnson

[f4igrad]

This will be my very first boat, I have never owned one before and I have never worked on one. However, I can read a manual well and I do all of my own work on my motorcycles, so I figure an engine is an engine. I am going to look at a 1975 Thundercraft boat with an 85 hp Johnson motor on it. It comes with a trailer as well. The guy knows nothing about the boat, he bought it from someone else, never used it, and told me that the previous owner told him the motor needs a tune up. Now that might be true, or perhaps the motor needs some serious work done to it. I have no clue, and neither does the seller. The good thing is that he is asking $800 for everything and I am going to try to talk him down to $600. I figure for that money, even if I can't get it running I can sell it for what I paid for it.<br /><br />What do you all think, will working on this engine be too complicated or do you think with a manual and some help with this board I might be able to pull it off? Any idea about this particular engine, its strengths, reliability, etc? Here are some pics of the setup:<br /><br />

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[rickdb1boat]

Re: Thinking of buying this boat with an 85 hp Johnson

Hi f4igrad<br /><br />Working on the motor should be no problem for you. But before you buy it, run down and get a compression tester at your local auto parts store and run a compression test on the motor. That will tell you if it's worth buying. Everything else, like waterpump replacement, lower unit service and tune-up procedure is well within your reach. There are plenty of people waiting to help you with that right here. A manual will be a must have also. Good motors if solid to start with. Others will chime in with their thoughts....

 

[tashasdaddy]

Re: Thinking of buying this boat with an 85 hp Johnson

pull the plugs, they should all look a like, if one is clean there probably and water leak, gasket,ect. remove the lower unit bottom drain plug, catch some lube in clear cup, look for water, small shavings on magnetic plug are ok, big chunks bad. paln on following the steps it the post "awakening a sleeping outboard" use red search function, top of page. order the model specific manual for that motor. @ kencook.com. thats a great beginner boat. use to have one similar w/ 85 Merc. good luck, keep us posted, and welcome the Iboats.

 

[f4igrad]

Re: Thinking of buying this boat with an 85 hp Johnson

excellent, thank you so far. I have never run a compression test before, are they pretty easy to do on-site? Also, how much would a compression tester cost me?<br /><br />Thanks!

 

[DJ]

Re: Thinking of buying this boat with an 85 hp Johnson

You can buy a comp. tester for $25.00. It's the best tool there is for judging the health of any engine.<br /><br />1. Pull all the spark plugs out.<br /><br />2. Install the comp. tester in the first spark plug hole, turn the motor over for about a 3-second count. Record the reading.<br /><br />3. Repeat the process for the other three cylinders.<br /><br />The compression should be 100, or better, but even more importantly is that all four are close to one another. Within 5-10%.

 

[f4igrad]

Re: Thinking of buying this boat with an 85 hp Johnson

i don't know if i could do a compression test because the boat needs a battery and a gas container. i think i am just going to buy the boat and bring it back to my house to work on it. hopefully the compression is good and I can get it up and running, but if not I can probably ebay it and get my money back. You will definitely be seeing me on here in the coming weeks

 

[hisey1]

Re: Thinking of buying this boat with an 85 hp Johnson

i never worked on a boat motor in my life before i bought a cheap boat that had a broken ring and piston and cylinder damage. i knew it was broke down going into it. i bought a model specific manual and asked a lot of questions on here and for a few hundred bucks and a few weeks of my time, i rebuilt the motor step by step out of the book. now i have a boat and motor that runs good and looks good. now i never worked on motorcycles or anything else. no doubt you can get the job done and if you feel you are getting a good deal with the condition of the boat and trailer, go for it. these guys are a wealth of info and can help you out with any questions you have, believe me.

 

[koolerb]

Re: Thinking of buying this boat with an 85 hp Johnson

I bought a boat with a bad motor about two years ago. I bought the factory manual and asked a lot of questions on iboats and at my local marina and got it done. It cost more than I expected. I bought all the name brand OMC parts, sealants, lubricants, etc., ouch! Like the earlier responders posted look for the big stuff, if you can’t find any major problems I don’t see how you can go wrong for $600.

 

[tashasdaddy]

Re: Thinking of buying this boat with an 85 hp Johnson

i agree with everyone. and there is no better pleasure than to sit at the dock, around all those high priced boats, with a oldie that is purring at idle. i'm running a 1955 15hp evinrude, 1971 merc 135, and 1973 tanaka air cooled. all idle and run better than the new ones. just TLC and regular maint.

 

[john king]

Re: Thinking of buying this boat with an 85 hp Johnson

I did this, started with a boat and no motor. T hen I got a junk boat and a motor. To make a long story short I now have two boats. They run good. I have an old motor that had bad compresion, all that is bad is the head gaskets. One of the problems you run in to is finding parts.

 

[f4igrad]

Re: Thinking of buying this boat with an 85 hp Johnson

ok folks, I bought the boat and towed it home today. it looks to be in pretty good shape, and the best part is that I got if for $600. I have taken some pics of the engine, would you mind taking a look at them? Let me know if you see anything I should immediately pay attention to. I don't know how long the boat has been sitting without being run, but I do know the registration for the boat expires this month, so it hasn't been sitting around for too terribly long. It is a 1975 Johnson 85 HP engine, model #85ESL75 E. <br /><br />BTW, I believe this engine is water cooled, but I want to work on it in my driveway. Can I start it for short periods of time without damaging it? Also, there is a small hole at the bottom center part of the boat, I assume for draining water. Shouldn't there be a plug for it? Right now it is totally open.<br /><br />Thanks for all of your help!<br /><br />

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[McGR]

Re: Thinking of buying this boat with an 85 hp Johnson

For starters... that starter drive needs some attention. It's supposed to slide up a helix machined into the motor shaft. From your picture, it looks like the whole works is rusted and frozen up. You want to take that apart and free it up. After you get the starter working. Then you can do a compression test. Assuming the compression checks ok, then you can work on the fuel and ignition systems.<br /><br />You can run the motor using "muffs" that provide water intake via a garden hose. Using muffs you can only run at RPMs below about 2K. So, you really can't load test on the drive. However, running on the drive/muffs will allow you to get the basic operation sorted out. By the looks of the pictures you will have some work to do before you will be testing on the drive. First do the compression test then check back. And, yes, it sounds like you need a drain plug for the boat.

 

[f4igrad]

Re: Thinking of buying this boat with an 85 hp Johnson

thank you!<br /><br />i am assuming that the starter is the cylinder looking thing in the first photograph, the one with the gunk at the top. i need to take it apart and clean it up? i am not sure what you mean by "slide up a helix." <br /><br />I have worked on motorcycle engines before, but the boat engine is new to me. I am ordering a service manual tomorrow from kencook.

 

[walleyehed]

Re: Thinking of buying this boat with an 85 hp Johnson

Take all the engine mount nuts off (one at a time) and replace them with stainless lock-nuts.<br />A stainless washer over the bolt before the nut wouldn't hurt either.<br />Looks like the airbox is missing the top 2 plastic plugs (they should be installed), and why is the main wiring harness disconnected???

 

[f4igrad]

Re: Thinking of buying this boat with an 85 hp Johnson

the main wiring harness was disconnected when I got there, but the other half of the harness is there, i just haven't connected it. <br /><br />Are the 2 airbox plugs essential? Is that a part I need to order or are they pretty generic?

 

[tashasdaddy]

Re: Thinking of buying this boat with an 85 hp Johnson

your first step. is to order the Johnson service manual, specifically, for your engine. suggest kencook.com. they are not cheap, but will become your favorite reading material. familarize you self with the book (read it). then you will understand what we are talking about, much better and ask more to the point questions. you are going to be depending on this engine to get you home. nothing worse than get stuck at dusk and no help around. i'm not being critical, just telling the truth. the more you know about this engine the safer your fun will be... it's extremely rewarding to sit at the dock with a 30 year old engine purring like a kitten, while all those new monthly payments are watching you, are sitting ther sputtering and spitting.

 

[G DANE]

Re: Thinking of buying this boat with an 85 hp Johnson

It looks like the link from the choke solenoid to the choke arm is missing, you might have a hard time starting it without choke. Looks like it sat for a while !! Check the procedures in FAQ, awakening a sleeping outboard, first. Dónt start it without water, "muffs" will do it.

 

[f4igrad]

Re: Thinking of buying this boat with an 85 hp Johnson

i am ordering a manual today, but i want to get started on the engine while the manual is on its way. should the big gear at the top (is this the flywheel??) be able to turn freely in my hand? I tried turning it but it wouldn't. I have moved most of the other levers on the engine and they move relatively freely. I can move the choke by hand, but I guess I need the choke arm to start it from the control box?<br /><br />Thanks again everyone!

 

[ezeke]

Re: Thinking of buying this boat with an 85 hp Johnson

I think that all of the choke parts are there, configurations change, but it looks right for the 75 models. Take a look at the parts diagrams for your motor here: BRP Parts Diagrams <br />You can see the choke linkage on the intake manifold diagram.<br /><br />If you haven't already bought the service manual, there is one on Ebay for 1975 85HP Evinrude (which is exactly the same as your Johnson except for decoration. Service Manual <br /><br />Take the spark plugs out and get some oil into the cylinders. The rings are probably stuck on the cylinder. Let the oil soak in for 24 hours and try the flywheel again(clockwise only). Don't force it.

 

[alden135]

Re: Thinking of buying this boat with an 85 hp Johnson

Originally posted by f4igrad:<br /> should the big gear at the top (is this the flywheel??) be able to turn freely in my hand? I tried turning it but it wouldn't. <br />

If you remove the spark plugs and cannot turn the flywheel, you have a problem. Something you could start with is spraying some tc-w3 or fogging oil in the cylinders and let it soak in.