Loss of Power...OMC 115 Turbojet

[troybuz]

Hi all,
I will try to get right to the point. I have a new power head for my OMC Turbojet, which is the 115 Crossflow.
I have been babying the motor through break-in, but have some concerning issues. The first issue that I had was a water intake (cooling supply) issue, where the intake line was smashed (squished between the engine hosuing and the jet pump casuing major restriction) casuing high temps...up to 190 or 200 degrees. I have solved the cooling issue and now seem to have a lack of power. My first thought was that I caused some damage when she got hot, but my compression is 125, 125, 120 and 118...which has been much the same since new.
The boat fires up an runs, but has far less power than when new, and the powerhead only has 6 hours.
The plugs look good color wise, however, it does lay down when reving making me think I have a fuel issue??? Timing is set at 4 degrees and 28 degrees as per the manual, and the carbs are freshly rebuilt.
I guess my question is, could the running a bit hot have casued damage that I can not detect with a compression check. If not, I assume I am either looking at fuel or electrical.
Thoughts?
Thanks,
Troy

 

[troybuz]

Re: Loss of Power...OMC 115 Turbojet

No posts, so I will offer more information.
The boat has a total of 100 hours on her. The first motor failed most likely from a cold water seizure, as I removed the themostats (per a poor recomendation).
The loss of power happended about the same time the engine started to sound different????
1. Carbs are rebuilt, but still could be the issue?
2. Could I have seized the motor, have OK compression, but it is slightly low.
3. Powerpack/ coil/ etc?
Any help????
Thanks
Troy

 

[tmfeaster]

Re: Loss of Power...OMC 115 Turbojet

No posts, so I will offer more information.
The boat has a total of 100 hours on her. The first motor failed most likely from a cold water seizure, as I removed the themostats (per a poor recomendation).
The loss of power happended about the same time the engine started to sound different????
1. Carbs are rebuilt, but still could be the issue?
2. Could I have seized the motor, have OK compression, but it is slightly low.
3. Powerpack/ coil/ etc?
Any help????
Thanks
Troy

Test your stator, powerpack, regulator/rectifier and coils. These can go bad during an overheat restricting power. It happened to me. Ended up being my coils, they melted a tad bit.

 

[troybuz]

Re: Loss of Power...OMC 115 Turbojet

After a water test today I found my timing off a bit, which helped...but only marginally. My gut tells me it's a fuel issue, but I can not rule out electrical. The rectifier is probably suspect, as I am not charging, and have sporatic tach issues.
Is there a way to trouble shoot these devices, or do you just throw money at them?
Thanks
Troy

 

[troybuz]

Re: Loss of Power...OMC 115 Turbojet

OK, a few more details.
I replaced the VRO Fuel PUmp with a non-VRO unit. This totally solved my high speed stall issues.
For the other loss of power, I found the reverse bucker has walked out of adjustment and was only raising about 1/2 the opening of the jet.
Most of my issues are getting solved.
With reguard to the tach not working and not charging, I ordered a new rectifier. In the meantime I notice that the ignition switch seems to eb suspect for the tach issues, as if I wiggle the key the tach will sometimes start to work. Thoughts?
Thanks,
Troy