TippyCanoe
Cadet
- Joined
- Jun 2, 2002
- Messages
- 7
I have a 1995 Boston Whaler Rage 15 (Jetboat) with an OMC TurboJet 115 engine. The engine starts easily, runs fine for about 30 minutes to an hour, and then the ignition shuts down. When this happens, I noted that there is no spark to any of the four spark plugs when I crank the engine. Periodically the engine will not crank after such an episode. Usually, though, after waiting quit a while, the engine will then start up again after it cools down, then shuts down again in about
10-15 minutes. The engine does not overheat though and the shutdown occurs at normal operating temperatures. When I run the engine in the driveway on a hose, it will run forever.
When the engine will not crank, I noticed that the flywheel was hard to turn by hand, but after removing any sparkplug it turned easily. After doing this, the engine tends cranks.
I took the boat to two different mechanics. Both times the engine did not shut down when they tested it (it needs to run a while in open water for the shutdown to occur). I had the first mechanic check out the whole system. He said everything seemed fine: good compression, good fuel system, good ignition system, good temperature. The second mechanic however said the VRO oil pump may not be working properly and triggering some safety switch to stop the ignition (although I do not believe this engine has that feature). He also thought that this may have cause some damage to the crankshaft, and hence the engine needs to be overhauled, althoughthe powerhead is fine. (There is quit a bit of engine noise at idle ? even for a jetboat ? but I cannot tell if it is from the flywheel, the crankshaft or the impeller housing.)
To test the second mechanics theory, I bypassed VRO2 pump and premixed the gas and oil at 50:1. The engine still shuts down after 30 minutes to an hour, i.e. it runs the same, and so I don't believe there is an oil problem.
My next step is to remove the flywheel and see if there is any damage under there. My guess is that there is a short somewhere, possible either the stator assembly or the powerpack. Perhaps something is loose which causes the short and always the cranking problems.
Anyways, if any one has any other ideas as to what could be causing this problem, I would love to hear them. Can a damage crankshaft cause such an ignition problem??
Thanks, Tippy
10-15 minutes. The engine does not overheat though and the shutdown occurs at normal operating temperatures. When I run the engine in the driveway on a hose, it will run forever.
When the engine will not crank, I noticed that the flywheel was hard to turn by hand, but after removing any sparkplug it turned easily. After doing this, the engine tends cranks.
I took the boat to two different mechanics. Both times the engine did not shut down when they tested it (it needs to run a while in open water for the shutdown to occur). I had the first mechanic check out the whole system. He said everything seemed fine: good compression, good fuel system, good ignition system, good temperature. The second mechanic however said the VRO oil pump may not be working properly and triggering some safety switch to stop the ignition (although I do not believe this engine has that feature). He also thought that this may have cause some damage to the crankshaft, and hence the engine needs to be overhauled, althoughthe powerhead is fine. (There is quit a bit of engine noise at idle ? even for a jetboat ? but I cannot tell if it is from the flywheel, the crankshaft or the impeller housing.)
To test the second mechanics theory, I bypassed VRO2 pump and premixed the gas and oil at 50:1. The engine still shuts down after 30 minutes to an hour, i.e. it runs the same, and so I don't believe there is an oil problem.
My next step is to remove the flywheel and see if there is any damage under there. My guess is that there is a short somewhere, possible either the stator assembly or the powerpack. Perhaps something is loose which causes the short and always the cranking problems.
Anyways, if any one has any other ideas as to what could be causing this problem, I would love to hear them. Can a damage crankshaft cause such an ignition problem??
Thanks, Tippy