Will My $700 Yamaha 90hp Outboard Run Again?

so for today I'm going to be fixing up a Yamaha 90 horsepower and the reason why I'm putting this intro in the beginning of the video is because I accidentally deleted some footage of me working on this engine in the beginning so it's gonna do a little quick overview this motor was posted on Craigslist for a thousand dollars I went there put my compression gauge on there and the middle and top cylinder were good but the bottom cylinder was at 70 psi while the other ones were between 115 and 120 psi and I noticed that someone tried to fix it because they changed a head gasket on it it was literally brand new so I gambled on and give him some hundred bucks took got home took the head off and this is what I found I found that there was a hole in the bottom of the cylinder head which was allowing water to go into my combustion chamber and it was allowing compression to escape so I'm going to start this video of where I purchased a used head for this engine so went out and I got a used head got this pretty cheap it was only 70 bucks and now I'm gonna put the head on with the new gasket and see how she runs and where the compressions at so let me do that so here's my head I'm gonna put my new gasket on torque all the bolts and then put my head gasket on and install it right on the motor and we'll see how she runs so now I'm gonna torque all this down torque specs will be on top of your head and you just follow the numbers on the bolts so you just start from number one then you go to two and three four five six seven eight nine and I have an electronic torque wrench so I just punch in the number and it does everything for me so this can be the first time since this motor has been started since the head was off can let it run see how rooms and do a compression check and see where we're at [Music] what I'm going to do now is I'm gonna pull the plugs out and I'm going to do a compression check and let's see where we're at so now I'm going to do a compression check starting from the top cylinder going down so the top cylinder reads about 118 psi now we're gonna do the middle one middle cylinder reads 115 psi so look at that the bottom cylinder reads 120 psi before I think it was like 70 or 80 psi so our problem is solved all these numbers are very acceptable and this is a good running motor so we have 118 115 and 124 this engine alright so the motor is and 100% running condition I could actually put on a boat and run it but look how ugly this head looks like on this block it's 2 different paints I'm gonna pull the power head off respray the whole power head so it's 1 collar and just gonna look a lot better I just want to give a little update I got the carbs off the electronics I was on the side I'm gonna take the flywheel off the state or underneath it and that's pretty much it left with the block it seems really complicated to take all the stuff off but it's on honestly really easy it took me about literally about 15 minutes to take everything off so anyone could do this if you're if you have a couple tools and a little bit of time so when you're taking the flywheel off you want one of these pullers you always want to put the nut back on like that because the flywheel is gonna pop up and you don't want that you know falling on the ground or hurting you know your alert leg or something so you're gonna give it some pressure here we're gonna stop there I'm gonna grab a hammer and usually it's gonna pop right here so let me take this impact off the gun here we go there it goes sorry Luce just like that now you have a key right there on the crankshaft so make sure you don't lose that put that somewhere safe so now I'm gonna take off the power head bolts all right so I just got all the bolts off that was holding the power head and how the power head is ready to come out I got a blonde flathead type deal and I just want to pry underneath the power head to try to break it loose and there she is she came right out it's really handy if you have one of these engine hoists because I pretty much does all the work so what I'm going to do now is I'm going to clean all this degrease it make it all clean get this ready to get painted tomorrow the base gasket for the power head and it goes under it was pretty rotted out I'm surprised that you know it wasn't leaking or anything but check this out pretty bad so today I'm gonna be working on the power head what I'm doing is I'm cleaning it up a little bit I have a wire brush on my drill and I'm just trying to get all the loose parts where it's a little bit corroded like on the water jacket over here there's a lot of paint that's flaked off so I'm gonna get all that you could see right here it was pretty bad right here is the paint it's all bubbly so I want to get all the loose stuff off him and degrease it dry it off and repaint it so now I'm in the process of decreasing this motor going to completely clean this motor as good as I can I'm gonna get a paint brush and try to get in all the crevices to get all that dirt off so the power head is ready to be painted I did take all the old paint off of the head that was on here taught everything I washed everything the grease everything it's all dried and everything's taped off [Applause] so what I'm doing now is I'm taking all the carbs off because just easy to do it and I'm going to inspect all the jets to make sure that they are not clogged up and they're free and I'm just gonna clean up whatever gunk is in the carb these are pretty clean already I could tell someone was already in here that put new gaskets and everything so which is a good sign but I'm still going to check them out and make sure they're ready to go so the carbs are ready to go I'm going to mount this directly on to the block that's hanging from my lift and I'm gonna start adding more stuff to it before I mount that power head back on the midsection [Music] so now I'm gonna be installing the power head in the midsection have a brand new Yamaha power head gasket that's gonna go in between the midsection and a power head so I'm going to show you guys what I got done the power head is pretty much all on just a few things that have to do like put the air box and stuff and the battery cables but it looks really good so I'm getting ready to put this motor on the boat I am changing the gear fluid in the lower unit as you could see it's not milky or anything which means that the seals are in good condition just gonna refill it with a new gear fluid and just gonna go right on my John boat right on the jack plate [Music] start right up [Applause] got the boat in the water motus running great it's been idling here since I dropped it in pumping great water can I go for a test-drive with it [Applause] moani's running good so far it's a kind of little wavy out and this boats a flat bottom so when I get on it it's a little sketchy so won't be going too fast today with it it's running great I'm gonna see if the inside of McDonald's is open to grab a couple of drinks couple burgers hopefully it's open so that McDonald's is closed but right across the street there's a Publix there probably get some subs and chicken tenders and we're gonna make it work we're heading out of here just had her lunch sir out here in the flats we're gonna see if we could catch anything we're using shrimp and hopefully we can get something good what is it she gets cabbage what is that red fish oh oh oh it's a catfish all right [Music] so got to this island I'm gonna put my drone up it's pretty low tide as she could see it as a pretty big up boat out there and he's having a hard time to get out it looks like he's getting stuck there hopefully he gets out of there but uh that motor came out looking pretty good after I painted it and everything starts right up no problems first key turn check this out [Applause] running great so it's getting dark we're gonna head to the boat ramp and gonna call it a day we're gonna call it a success on this Yamaha 90 [Music] and we made it back safely so it's finally got the boat out it's time to go home and it was a great opportunity to work on this motor and to say that it's amazing how you could buy a cheap motor and do a few things to it and should be a good running engine so if you guys like this video please comment like and subscribe and I'll continue making outboard videos and boat videos thank you [Music] [Music] [Music] [Music]

Channel: ThatBoatGuy

Views: 402,431

Rating: 4.9535336 out of 5

Keywords: outboard, 2 stroke, 4 stroke, engine, motor, longshaft, shortshaft, tiller, flats boat, hewes, starcraft, criscraft, aquasport, carolina skiff, yamaha, mercury, nissan, tohatsu, honda, suzuki, omc, etec, mariner, evinrude, 9.9hp, 15hp, 20hp, 25hp, 30hp, 40hp, 50hp, 70hp, 90hp, 115hp, 150hp, 175hp, 200hp, project, fixing, thatboatguy

Id: OSL548Zv6T4

Length: 14min 59sec (899 seconds)

Published: Sat Mar 28 2020