I have a 1998 Reinell Coho 210C powered with a 5.7 Liter V8 2bbl mercarb and thunderbolt V ignition. The prop on the boat is a stainless vengeance 19 pitch and it's an Alpha 1 sterndrive. I want to make this post and continue posting so I can help anyone who has or is experiencing similar problems. Feel free to post if you have any input but my plan is to walk you through the whole ordeal until the solution has been found and it's back up and running well.
Purchased the boat approximately 2 months ago or less. When I test drove etc. it ran flawlessly. The motor started easily and literally ran "like a top". Great top end speed.. easy to get up on plane etc.
The hour meter has 169 hours. Didn't realize it until later but later discovered this was not the original motor. In part I figured that out after suffering the issues and doing some research. Long story short the original mercruiser was replaced with a Volvo GM motor at some point. Basically the same motor but clearly not the original.
This boat flat hauled some butt. It would do 48.3 mph WOT with 3/4 tank of full (100 gallon tank) and two people on board. RPM was 4500+.
Slowly but surely I noticed a slight decrease in RPM and top end speed, over a period of 5 or 6 boat trips. 4100 RPM's and 40 mph top end. Also I would hear a vibration type noise, at least I thought it was vibration. I've since learned what I was hearing at high RPM was pre-ignition sounds.
Boat started to become a hard starter and one time I flooded the motor and it dieseled and aspirated fuel up the intake. Decided to change the plugs. Pulled the #1 hole plug and found and NGK iridium plug. Later learned this was the wrong plug for this motor but not until I bought and installed 8 fresh ones. During install a friend was helping and thought he broke one of the ceramics but then assured me it was ok.. (don't let a diesel mechanic work on your boat haha).
Boat started much easier after plug change and ran smooth at idle. Went out fishing with a buddy and it would still make that chatter pre-ignition noise at high RPM and boat still felt sluggish to me. After fishing trip boat seemed to idle a little rougher.
Next time out crusing at 30-35 mph and all of the sudden started losing power. Put it in neutral and kept it running but it ran horribly like it was loading up and not running on all cylinders. pulled some plug wires while it was running and no change on 3 or 4 holes. Limped it back to the dock and pulled the plugs finding the plug in #4 hole with a cracked ceramic and the electrode strap partially missing (broken or burnt off). Figured I had found my problem and that my buddy had actually broken a ceramic.
Went to the marine store and bought the correct spark plugs, a new rotor and cap (they looked old and weathered) and a new ignition coil for good measure. Installed it all thinking it would run like a champ but nope.. still rough as heck and acted like it was loaded upon on fuel. Got it cleaned out and it ran ok. Took it out on the water and same thing. Checked the timing without putting it in base timing mode and it looked way advanced even at idle. Couldn't get it to run at 650 rpm's. When on the water and up at WOT had my buddy retard the timing slightly and the pre-ignition noise went away but as soon as we came to idle it loaded up and ran like crap again.
Pulled it out of the water and did a compression check on the motor with the following results (cold motor): #1 150 psi #3 150 psi, #5 80 psi, #7 0 psi #8 0 psi and quit checking. Got the leak down tester out and found leakdown through the intake (nothing out of exhaust or the crankcase) indicating intake valves. Boroscope in the cylinders confirmed.
Pulled the cylinder heads off the motor and found tuliped (cupped) intake valves on 4 cylinders. No damage to pistons and all cylinders looked good with tight cross hatching.
Realizing Tuliped valves are a symptom and not a problem I am in search of the problem. Took the cylinder heads to a machinist (former drag racer and engine builder) and he said it's timing or fuel.. Duh! Talked to a marine mechanic and he said without damage to pistons it's going to be fuel related.
I have not run old fuel in this boat. I don't run premium but I do use ethanol additive. I have put 200 gallons through this boat in the two months I've had it. It's fresh.. dumped fuel water separator into jar.. zero water noticed.
When it would idle I did notice fuel dribbling from one side of the carb venturi but not the other.. Don't think I should see any dribbling from either but dribbling would be more likely to cause a fat condition not a lean condition from what I know.
Fuel pump has good pressure.
My plan:
Have the heads re-done and use stainless intake valves
Put a new carburetor on the motor
Replace all plug wires and all spark plugs
Replace distributor sending unit and time correctly
Replace risers (it's a closed cooling system and the risers look like they've seen better days).
Replace any noticeable deteriorated wires or connectors
Replace fuel filter
Replace oil & Oil filter
Change prop from 19 pitch to 17 pitch prop
Anyone have any comments, ideas or suggestions??
Purchased the boat approximately 2 months ago or less. When I test drove etc. it ran flawlessly. The motor started easily and literally ran "like a top". Great top end speed.. easy to get up on plane etc.
The hour meter has 169 hours. Didn't realize it until later but later discovered this was not the original motor. In part I figured that out after suffering the issues and doing some research. Long story short the original mercruiser was replaced with a Volvo GM motor at some point. Basically the same motor but clearly not the original.
This boat flat hauled some butt. It would do 48.3 mph WOT with 3/4 tank of full (100 gallon tank) and two people on board. RPM was 4500+.
Slowly but surely I noticed a slight decrease in RPM and top end speed, over a period of 5 or 6 boat trips. 4100 RPM's and 40 mph top end. Also I would hear a vibration type noise, at least I thought it was vibration. I've since learned what I was hearing at high RPM was pre-ignition sounds.
Boat started to become a hard starter and one time I flooded the motor and it dieseled and aspirated fuel up the intake. Decided to change the plugs. Pulled the #1 hole plug and found and NGK iridium plug. Later learned this was the wrong plug for this motor but not until I bought and installed 8 fresh ones. During install a friend was helping and thought he broke one of the ceramics but then assured me it was ok.. (don't let a diesel mechanic work on your boat haha).
Boat started much easier after plug change and ran smooth at idle. Went out fishing with a buddy and it would still make that chatter pre-ignition noise at high RPM and boat still felt sluggish to me. After fishing trip boat seemed to idle a little rougher.
Next time out crusing at 30-35 mph and all of the sudden started losing power. Put it in neutral and kept it running but it ran horribly like it was loading up and not running on all cylinders. pulled some plug wires while it was running and no change on 3 or 4 holes. Limped it back to the dock and pulled the plugs finding the plug in #4 hole with a cracked ceramic and the electrode strap partially missing (broken or burnt off). Figured I had found my problem and that my buddy had actually broken a ceramic.
Went to the marine store and bought the correct spark plugs, a new rotor and cap (they looked old and weathered) and a new ignition coil for good measure. Installed it all thinking it would run like a champ but nope.. still rough as heck and acted like it was loaded upon on fuel. Got it cleaned out and it ran ok. Took it out on the water and same thing. Checked the timing without putting it in base timing mode and it looked way advanced even at idle. Couldn't get it to run at 650 rpm's. When on the water and up at WOT had my buddy retard the timing slightly and the pre-ignition noise went away but as soon as we came to idle it loaded up and ran like crap again.
Pulled it out of the water and did a compression check on the motor with the following results (cold motor): #1 150 psi #3 150 psi, #5 80 psi, #7 0 psi #8 0 psi and quit checking. Got the leak down tester out and found leakdown through the intake (nothing out of exhaust or the crankcase) indicating intake valves. Boroscope in the cylinders confirmed.
Pulled the cylinder heads off the motor and found tuliped (cupped) intake valves on 4 cylinders. No damage to pistons and all cylinders looked good with tight cross hatching.
Realizing Tuliped valves are a symptom and not a problem I am in search of the problem. Took the cylinder heads to a machinist (former drag racer and engine builder) and he said it's timing or fuel.. Duh! Talked to a marine mechanic and he said without damage to pistons it's going to be fuel related.
I have not run old fuel in this boat. I don't run premium but I do use ethanol additive. I have put 200 gallons through this boat in the two months I've had it. It's fresh.. dumped fuel water separator into jar.. zero water noticed.
When it would idle I did notice fuel dribbling from one side of the carb venturi but not the other.. Don't think I should see any dribbling from either but dribbling would be more likely to cause a fat condition not a lean condition from what I know.
Fuel pump has good pressure.
My plan:
Have the heads re-done and use stainless intake valves
Put a new carburetor on the motor
Replace all plug wires and all spark plugs
Replace distributor sending unit and time correctly
Replace risers (it's a closed cooling system and the risers look like they've seen better days).
Replace any noticeable deteriorated wires or connectors
Replace fuel filter
Replace oil & Oil filter
Change prop from 19 pitch to 17 pitch prop
Anyone have any comments, ideas or suggestions??
