92 Mariner 150, slow throttle response

BTL

Petty Officer 2nd Class
Joined
Feb 22, 2017
Messages
106
Took my project boat out for it's first fishing trip last weekend and overall I'm happy with how it performed. It's a 1989 Wellcraft 18 Sport with a 1992 Mariner 150. I've done a lot of work to the boat, engine, and trailer over the last 10 months, so it felt really good to put it to use!

There was one quirk though, when I'm throttling up, it takes a few seconds for the motor to "catch up" to the speed it should be based on throttle position. Seems to happen when I'm going from about 1/2 to 3/4 open, and then runs fine afterward. Unfortunately I didn't watch the tach so I'm not sure about RPMs at the surge, but it runs right around 5000 at full throttle.

The engine has new plugs, new voltage regulator, new switch boxes, new fuel filter and fuel/water separator, and all 3 carburetors were cleaned and rebuilt recently. I removed the oil injection system so I use 50:1 premix. Put in 20 gallons of fresh gas before I hit the water.

Seems like a problem with fuel flow to me, hoping it's not electrical.

Any past experiences with this issue or suggestions on where I should start looking?


Serial # OD177534
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,215
Does it hesitate accelerating from idle? If so, that would be a too lean idle mixture. Not sure what t suggest for your issue though. Is the compression good?
 

BTL

Petty Officer 2nd Class
Joined
Feb 22, 2017
Messages
106
No it's ok from idle, it only hesitates when I'm increasing speed.

Last time I checked compression I had one cylinder at 95psi, and the other 5 were at 120. That was probably 4 months ago and I've replaced the head gaskets since then, so it may be different now.
 
Top