1978 75 hp bogging down under load

[Delta Stinger]

Hello,I just purchased a boat that has a 1978 75 HP stinger motor that needs a little help to get going. It wasn't circulating water so I replaced the water impeller thanks to all of the great threads on the subject but I took it out to the water and when I started throttling up the motor would die out.

I think I am going to replace the fuel pump diaphragm and also rebuild the carburetors (gas coming out of air intake). I don't have the special jet removal tool but I think i'll try to make some based on other threads. I also was going to replace all of the gaskets (it needs some done might as well do them all) but I wanted to know if I should/need to replace the crank seals while I have it apart or if its really a lot more work that's not necessary?

I am mechanically inclined but i don't have any experience working on outboards so I got the factory service manual to help me out as well as utilizing this awesome site. I'm trying to spend as little as possible on the motor but I want to make sure that I get it done right so that I don't get stranded anywhere. Any suggestions? Anything else I might have to check on?

 

[fireman57]

Re: 1978 75 hp bogging down under load

First of all, welcome to iboats. When you clean the carbs just use the wire from a bread wrapper twist tie an go through every jet and orafice. There are also 4 small holes in the pickup tube.Then blow it all out with a good carb cleaner and compressed air. don't worry about taking out your high speed jet but make sure it is clean. I wouldn't replace any parts, except the impeller which you already did, unless they are bad. Once you get your carbs clean I think you will be ready to go.

 

[Delta Stinger]

Re: 1978 75 hp bogging down under load

Thanks for the information Fireman, I have the parts on order for the carb rebuild kits and they should get here tomorrow. I plan on just changing the gaskets because I think they are originals and I know that some have deteriorated. I figure if I already have to take off the power head once then i'll just do it all togther so I won't be doing the same job twice a couple years down the line.

Thanks for the tip about the thin wire i made sure to save a couple for the job. When i take it apart should I be measuring or marking positions of any bolts or anything else?

My dad was trying to tell me the adjustment needed to be the same so I would need to count how many turns before it goes all the way in and then reinstall in the reverse the same number of turns out. This is the first time I'm rebuilding a carb so I want to do it right. He also told me to clean the old carbs in OMC engine tuner and to let them soak the rinse with water and blow out with compressed air and I want I want to make sure this is ok. Sounds good to me but I wanted to make sure. Thanks for all our your help, I have some fun to look forward to on my day off Thursday

 

[pn]

Re: 1978 75 hp bogging down under load

don't forget your fuel pump rebuild. sounds like your very careful, so i wouldn't worry about the rebuild.

 

[fireman57]

Re: 1978 75 hp bogging down under load

I don't understand why you are worried about the crank seals and rebuilding. Are you having some other trouble? You don't need to remove the powerhead for a simple carb job. Also, you will either need to buy or make a special screwdriver to remove the high speed jet.There are a couple of threads on here how to make one. Just do a search at the top of the page.

 

[wrmdunker]

Re: 1978 75 hp bogging down under load

Here is what I used to get my high speed jet out of my 1974 70hp. Small screwdriver set commonly available.