Hello, first time poster here, long time follower. I have a 2005 Crownline 180 with a 4.3 MPI in it. Engine serial # is 0W333843. When I start the engine it does not fire off like I am used to with a Fuel injected engine, it just kind of slowly sputters until it gets to idle rpm. Once idling it seems to run smooth. When the engine is cold, the boat hops up on plane in about 1-2 seconds, but when it is warm, it turns into a dog. I had a 19p 3 blade prop on it and it would run 54 mph (gps) at 4800 rpm, Now I have a 17p 4 blade on it and it runs 48 mph but it over revs. Performance is good once on top of the water and at high speeds/ rpms. I really started questioning the performance of this when I was pulling a single tube with 3 kids on it and only me in the boat And I struggled very badly to get on plane (I pull this same tube behind my dads 90hp fishing boat and you cant even tell its back ther) After this is where I started troubleshooting and noticed a few things that indicate there is a problem, but I can’t figure out why. I have a Techmate Pro and there are no codes. Here is what I have done so far
1. Replaced Distributer cap (its the HVS flat top) and rotor. (The old one was corroded so bad Im surprised it even ran)
2. New spark plugs
3. Ohmed plug wires (all checked perfect) and checked about 10 times that the wires are on the correct terminals.
4. New IAC Valve
5. New Fuel/water separating filter (old one was less than a year old, and zero signs of water or contamination)
6. Compression test. All cylinders at 185 psi +/- 2
7. Cylinder leakdown test. Range from 75/80 to 77/80 (on a cold engine)
8. Fuel pressure goes smack to 43psi when I turn the key on, and slightly lower when running.
9. Checked all 6 wires with a plug gap tester and have a strong spark at every cylinder.
10. Checked rotor position and it is dead smack on the little (6) with number one at TDC.
11. New thermostat, rock solid at 160. replaced because the previous one was faulty and engine would not heat up.
Now, here is where things get interesting.
When the engine is not running the Techmate is showing the timing is commanded at 8° BTDC (which seems about right to me), but when I start it, it goes to zero degrees. As the engine warms up, the timing gets more and more retarded to about 9° ATDC. I used a timing light as well To verify, and even though there is not a degree scale, it is clearly firing after TDC. If i Increase RPM’s the timing will advance. The other thing is that it is only pulling about 10” HG of vacuum at idle, and the needle is steady. Would have expected to see somewhere around 18”. checked for intake leak, with carb cleaner and propane, and nothing found. All sensors and switches are within their normal values. All wires and grounds are good and tight. New battery that is fully charged. Fuel vent tube is clear.
Is there anything else that would cause the timing to be so far off? Other than maybe the computer. Again, its an MPI, so the timing is not adjustable. Im kind of at my wits end with this thing.
Thank you.
1. Replaced Distributer cap (its the HVS flat top) and rotor. (The old one was corroded so bad Im surprised it even ran)
2. New spark plugs
3. Ohmed plug wires (all checked perfect) and checked about 10 times that the wires are on the correct terminals.
4. New IAC Valve
5. New Fuel/water separating filter (old one was less than a year old, and zero signs of water or contamination)
6. Compression test. All cylinders at 185 psi +/- 2
7. Cylinder leakdown test. Range from 75/80 to 77/80 (on a cold engine)
8. Fuel pressure goes smack to 43psi when I turn the key on, and slightly lower when running.
9. Checked all 6 wires with a plug gap tester and have a strong spark at every cylinder.
10. Checked rotor position and it is dead smack on the little (6) with number one at TDC.
11. New thermostat, rock solid at 160. replaced because the previous one was faulty and engine would not heat up.
Now, here is where things get interesting.
When the engine is not running the Techmate is showing the timing is commanded at 8° BTDC (which seems about right to me), but when I start it, it goes to zero degrees. As the engine warms up, the timing gets more and more retarded to about 9° ATDC. I used a timing light as well To verify, and even though there is not a degree scale, it is clearly firing after TDC. If i Increase RPM’s the timing will advance. The other thing is that it is only pulling about 10” HG of vacuum at idle, and the needle is steady. Would have expected to see somewhere around 18”. checked for intake leak, with carb cleaner and propane, and nothing found. All sensors and switches are within their normal values. All wires and grounds are good and tight. New battery that is fully charged. Fuel vent tube is clear.
Is there anything else that would cause the timing to be so far off? Other than maybe the computer. Again, its an MPI, so the timing is not adjustable. Im kind of at my wits end with this thing.
Thank you.
