I am in serious need of some solutions with an ongoing problem. 1995 Mariner 225 EFI OG276668 is having alot of trouble getting my 20ft Nitro on plane. Happens really bad when engine is tilted down to get on plane, almost like it is suffocating. Engine has been very well taken care of and cranks perfect, idles perfect, and runs at WOT at approximately 63 mph/5700rpm with two passengers and moderate load. Some days it will wind up perfectly and get boat on plane great but here lately it seems to have more and more trouble. Past two trips its embarrassing when I leave the ramp. I bought the boat with a 26P Trophy and it used to turn it fine. I have since put a 24P Trophy plus on it to help with the planing issues, but it hasn't helped much. Here is what has been tested thus far.
Compression (approx 100-103 on all 6), Spark test (jumped 3/8 gap all 6), new Champion QL77c plugs, new electric fuel pump and filter (old one had 32psi on gauge), injectors have been cleaned and flow tested, New Boyesen Reeds, New engine air temp sensor, new block temp sensors, new thermostats, fuel line and primer bulb (about 2 yrs old now), TPS sensor set and measured with Merc harness (idle 0.97, WOT 3.70). I put the reeds in it to help with idling, which they did and I also put the 250hp 4 butterfly intake on it hoping that more air would help with holeshot. This helped my wot and increased my speed by 4mph but didn't help the holeshot like I hoped.
I have run quickleen through it routinely along with nonethanol gas and I only run Merc oil in it. I am getting very frustrated as this engine should launch this boat fine and should probably push it faster too but I can't nail anything down as a cause. I have a service manual but everything checks out that I can check without Mercs DDT. Like I said, once boat is one plane it runs great but just stumbles under load. Thanks for any and all advice in advance@!
Compression (approx 100-103 on all 6), Spark test (jumped 3/8 gap all 6), new Champion QL77c plugs, new electric fuel pump and filter (old one had 32psi on gauge), injectors have been cleaned and flow tested, New Boyesen Reeds, New engine air temp sensor, new block temp sensors, new thermostats, fuel line and primer bulb (about 2 yrs old now), TPS sensor set and measured with Merc harness (idle 0.97, WOT 3.70). I put the reeds in it to help with idling, which they did and I also put the 250hp 4 butterfly intake on it hoping that more air would help with holeshot. This helped my wot and increased my speed by 4mph but didn't help the holeshot like I hoped.
I have run quickleen through it routinely along with nonethanol gas and I only run Merc oil in it. I am getting very frustrated as this engine should launch this boat fine and should probably push it faster too but I can't nail anything down as a cause. I have a service manual but everything checks out that I can check without Mercs DDT. Like I said, once boat is one plane it runs great but just stumbles under load. Thanks for any and all advice in advance@!