Popping noise at 3/4 throttle/ 89 3L 4CYL

[djshawnc]

Hello,

I have an 89 OMC 3L 4cyl engine in my Bayliner cuddy. After fixing a few problems, I went to take my boat out and at start up, I had to give it some throttle. It idled ok, and then when I went to go, I heard a popping noise from the carb. It ran fine at no-wake speeds, but as soon as I gave it more throttle, it bogged down and the popping started up. Reduced throttle, and it was fine. I read some posts, and determined it could be lean gas, timing, or compression. I treated the gas, and changed the fuel filter. (I bought a fuel water separator, but the one the marina gave me didnt fit so I just emptied it, and put fresh gas before putting it back on.)

Compression test: This was weird, because I only got a reading from the first cylinder. Not sure why, but I did double check, and my results were consistent. I can feel the pressure coming out, so there must be something there...

Notes: My neighbor attempted to adjust the timing manually (based on how it ran), and we did get it to a spot where it sounded better. All plugs were changed today.

What I have now: Hard to start. Needs just a little throttle to get it going. Sometimes ildes ok, sometimes not. Still makes the popping noise at 3/4 throttle and up. However, if I let it "Idle" with a little throttle, it sounds great.

New to boating, so I appreciate any help.
Thanks in advance.

 

[john4040]

Re: Popping noise at 3/4 throttle/ 89 3L 4CYL

with those comp #s it sounds like the head gaskt what dose the oil look like

 

[fishrdan]

Re: Popping noise at 3/4 throttle/ 89 3L 4CYL

Notes: My neighbor attempted to adjust the timing manually (based on how it ran), and we did get it to a spot where it sounded better. All plugs were changed today.

What I have now: Hard to start. Needs just a little throttle to get it going. Sometimes ildes ok, sometimes not. Still makes the popping noise at 3/4 throttle and up. However, if I let it "Idle" with a little throttle, it sounds great.

Timing by "ear" could cause serious engine damage once you have the engine running right. You need a timing light, then set it properly.

What were your comp #'s?

What have you done for tune-up items, plugs wires, points, condenser, fuel filters.

Sounds like you have a fuel system issue, along with other problems....

 

[sea wolf]

Re: Popping noise at 3/4 throttle/ 89 3L 4CYL

Timing by "ear" could cause serious engine damage once you have the engine running right. You need a timing light, then set it properly.

What were your comp #'s?

What have you done for tune-up items, plugs wires, points, condenser, fuel filters.

Sounds like you have a fuel system issue, along with other problems....

Yea, u need a timing light. You can pick one up at Harbor Freight for less than $15 bucks.