Sman0624
New Member
I wanted to get your opinions on this issue, it's driving me nuts.
Boat is a 1997 215 Express Cruiser Alpha1 Gen 2
Engine is a 5.7 L EFI with Delco HEI ignition.
Here's the issue. When I take the boat out it runs fine, strong starts and lots of power. Then after about 45 minutes of operation I would notice that when I give it anything over half throttle the engine surges, ocassional backfire through the throttle body (carb, the engine is fuel injected), just a total lack of power. When this happens the tach will jump all over the 4,000 to 5,000 range even though I know I'm only doing about 3,300 to 3,500 RPM. Note: When "cold" the engine runs fine and the tach does not jump.
After a pressure check of the electric fuel pump I found it was losing pressure and I was running lean (fuel starved which explains the backfire). After replacing the fuel pump the problem came back. I did the basics also, fuel seperator (fine, no contamination), anti-siphone valve, new plugs, cap, rotor, wires, electronic control module in the distributor yet the problem still occurs. All wire connections are clean and good.
I'm thinking a bad coil?? In the process of doing a compression check but I doubt that is the issue otherwise the engine would run bad all the time and not just after the first hour..correct? It's not bad fuel either otherwise the problem would be there all the time. I'm thinking electrical since the problem is worse after things heat-up.
What are your thoughts? Has anyone ever had this problem and if so then what did you do.
Thanks for your input.
Boat is a 1997 215 Express Cruiser Alpha1 Gen 2
Engine is a 5.7 L EFI with Delco HEI ignition.
Here's the issue. When I take the boat out it runs fine, strong starts and lots of power. Then after about 45 minutes of operation I would notice that when I give it anything over half throttle the engine surges, ocassional backfire through the throttle body (carb, the engine is fuel injected), just a total lack of power. When this happens the tach will jump all over the 4,000 to 5,000 range even though I know I'm only doing about 3,300 to 3,500 RPM. Note: When "cold" the engine runs fine and the tach does not jump.
After a pressure check of the electric fuel pump I found it was losing pressure and I was running lean (fuel starved which explains the backfire). After replacing the fuel pump the problem came back. I did the basics also, fuel seperator (fine, no contamination), anti-siphone valve, new plugs, cap, rotor, wires, electronic control module in the distributor yet the problem still occurs. All wire connections are clean and good.
I'm thinking a bad coil?? In the process of doing a compression check but I doubt that is the issue otherwise the engine would run bad all the time and not just after the first hour..correct? It's not bad fuel either otherwise the problem would be there all the time. I'm thinking electrical since the problem is worse after things heat-up.
What are your thoughts? Has anyone ever had this problem and if so then what did you do.
Thanks for your input.
Last edited: