I have a 1989, 3.7 MerCruiser the infamous 470. Apparently I’m not 100% sure.
I ran a compression test because I’m having this seasonal issue with carburetor’s. I’m on my third one all rebuilt several times because of stalling issues after running for about 60 seconds. No this seems to have occurred on all three carburetors. I will say that none of them are new. I bought some decent looking used ones bought a rebuild kit and did it myself I’ve been rebuilding carburetor since I was 20. so my first question is a compression test because I did the head gasket three years ago as precautionary because I heard these things can overheat so I did a dry test cylinders on cylinders 1 2 3 they all came to 150 on the last cylinder in the back I came up to 130. NowI did a wet test and the wet test came up with all four cylinders 150. Is that acceptable on cylinder four of being 20 PSI off?
My next question is, should I purchase a carburetor and enough with rebuilding these things I replace the fuel pump I was suspicious that there might’ve been air in the line because it has that same scenario. I saw a YouTube video and it was showing a guy that was starting off his boat and running perfectly fine for about 90 seconds, then it would bog and almost stall he would then put it in neutral, and it would slowly regain idle.
He was not able to go full throttle again for at least two minutes and then the second he gave it full throttle, and It did the same thing. Well it turns out that he had air pockets. That’s why I’m changing the fuel pump again. I also heard that these fuel pumps can go bad after a while. My fear is I buy a carburetor for $150 or $200 and it doesn’t solve my problem and it turns out it was something else.
Right now all three carburetors the second I try to accelerate it or give it some gas it just bogs down and dies, I’m using an electric pump for fuel or the mechanical fuel pump. In both cases, the carburetors do the same thing with all three carburetors. My buddy is convinced that there’s something in the fuel tank but I replace the anti-siphoning valve and tube for the fuel tank so there’s no clogging there. What strange is one time last summer? I took my friend out and I want to model think we can make it from one into the lake to the other but he said screw and give it a shot and we able to go from one end to the other with no problems 80% throttle we went for a swim.
We did the same thing on the way back, but it started to Bog and buck. I had to throttle back, and we had to idle all the way back in every time I tried to give it gas. It was just shutter and almost die so I quickly throw it back into neutral let the idle straighten out and catch up and then put it back into gear. I would just like to have one great summer where I can go from one into the lake with the other like I used till two years ago without any problems. I don’t mind buying a carburetor what I do. Mine is buying a carburetor and having the same issue going great I just threw away $150 that’s not my style because I’m a mechanic and I usually fix everything myself whether it’s cars or the boats.
I ran a compression test because I’m having this seasonal issue with carburetor’s. I’m on my third one all rebuilt several times because of stalling issues after running for about 60 seconds. No this seems to have occurred on all three carburetors. I will say that none of them are new. I bought some decent looking used ones bought a rebuild kit and did it myself I’ve been rebuilding carburetor since I was 20. so my first question is a compression test because I did the head gasket three years ago as precautionary because I heard these things can overheat so I did a dry test cylinders on cylinders 1 2 3 they all came to 150 on the last cylinder in the back I came up to 130. NowI did a wet test and the wet test came up with all four cylinders 150. Is that acceptable on cylinder four of being 20 PSI off?
My next question is, should I purchase a carburetor and enough with rebuilding these things I replace the fuel pump I was suspicious that there might’ve been air in the line because it has that same scenario. I saw a YouTube video and it was showing a guy that was starting off his boat and running perfectly fine for about 90 seconds, then it would bog and almost stall he would then put it in neutral, and it would slowly regain idle.
He was not able to go full throttle again for at least two minutes and then the second he gave it full throttle, and It did the same thing. Well it turns out that he had air pockets. That’s why I’m changing the fuel pump again. I also heard that these fuel pumps can go bad after a while. My fear is I buy a carburetor for $150 or $200 and it doesn’t solve my problem and it turns out it was something else.
Right now all three carburetors the second I try to accelerate it or give it some gas it just bogs down and dies, I’m using an electric pump for fuel or the mechanical fuel pump. In both cases, the carburetors do the same thing with all three carburetors. My buddy is convinced that there’s something in the fuel tank but I replace the anti-siphoning valve and tube for the fuel tank so there’s no clogging there. What strange is one time last summer? I took my friend out and I want to model think we can make it from one into the lake to the other but he said screw and give it a shot and we able to go from one end to the other with no problems 80% throttle we went for a swim.
We did the same thing on the way back, but it started to Bog and buck. I had to throttle back, and we had to idle all the way back in every time I tried to give it gas. It was just shutter and almost die so I quickly throw it back into neutral let the idle straighten out and catch up and then put it back into gear. I would just like to have one great summer where I can go from one into the lake with the other like I used till two years ago without any problems. I don’t mind buying a carburetor what I do. Mine is buying a carburetor and having the same issue going great I just threw away $150 that’s not my style because I’m a mechanic and I usually fix everything myself whether it’s cars or the boats.
