1979 Johnson 100 HP Questions

[Go'N'Gulfin 79]

HELP!!
My husband has been wanting a boat forever. I found an old boat but in good shape. I think? I don't know a whole lot about boats but learning. It's a 84' 19ft.Sea Nymph Striper with a 79' 100hp Johnson. I got to Miss. to buy the boat for Father's Day. We took it to the water and the battery was dead. " that's what he told me". So we take it back to their place and he hooked up to a hose . It started after he messed around with it for about 2-3 mins. I paid 1,200.00 for boat W/Motor and the trailer. I'm having the floor redone because there was a little rotted wood back by the motor. I unplugged the back and it drained for a good while. There was leaves, cans, tackle, u name it! All around the battery and all the wiring. When you try to start it, it makes a backfire noise then sounds like it doesn't want to idle. A little smoke came out but he said it had been sitting for a while. I'm worried I bought someone else's problem. Other than that I love the boat. Great project for the family to jump into and enjoy afterwards. My question is, Is this something fixable? Or should I give him the boat and save for a motor?

 

[GA_Boater]

Welcome to iboats, Go'N'Gulfin 79.

Moved these into your own thread. Look at the Help Tips on top of the page.

I'm sure you will get some more questions along with some help.

 

[emdsapmgr]

Before you do anything regarding engine repairs, do a compression check first. A new 100 hp engine in 1979 would have had 125 lbs compression on each cyl. Check your cyl compressions vs that standard. If the compression is over 10% low on a cyl, it may be in need of some significant repairs. You'll need to evaluate whether you really want to dump some more $ into it or not. If the compression comes up good on all 4 cyls, the engine may well be worth putting some add'l cash into it. Since you've got a possible misfire, first thing to check would be the flywheel key. If it's sheared it will be out of time and won't run. Next would be to determine if you have spark on all 4 spark plugs or not. These are all basic items and should be done before you get into other issues, such as a new water pump impeller, possible carb overhauls and maybe new thermostats.

 

[ctdude]

Hi,
I am new to this forum too and have almost zero knowledge about outboard engines (in fact any engines!), however I am in a very similar situation to yourself, so for whats its worth, if nothing else, maybe I can give you some emotional support. haha.

I am currently trying to start a 1979 75hp Johnson, so im possibly worse off than you. The first thing I did was test my starter motor, which works, and yours does too, so we are even there. The next thing i did was a compression test, and when people talked about it i thought it would be difficult but it was actually very simple. You may already know how to do it, but if you don't there are plenty of people on here (myself included now!) who can help with this.

After i did this I knew my motor was worth proceeding with, at least to the next problem (i'm at that problem already, haha).

Do a compression test and then you will know whether you want to proceed further with the motor. If you need help with this, ask the good folk on here.

Hope this helps. Good luck!