Johnson V4 Powerpack question

[jetsled74]

Model number of engine is J90TLETS........V4 90hp/65 jet.. Original problem was motor was running at what appeared like 25% of normal operation speed. Power pack was replaced all is well running on hose however now when its put on full throttle on water it reaches full speed up on plane the cuts out to like 25% again. It doesnt stall just looses power. I put back in neutral can take off full speed again only to have it cut out again. Fuel is ok its not losing prime. My confusion is in making sure correct powerpack was installed. I see two listings for cdi packs 88models 90/100/115 models says part# 113-2028..... Then theres a listing for 65/80jetmodels part#113-430.. The 113-430 is what it was replaced with. Without having the original i want to cross and make sure correct was installed. Any help would be appreciated.. This problem has me stumped as to why i keep losing power but when i place in neutral and take off all is well again. I am wondering if its voltage related since i ruled out fuel starvation.

 

[Daviet]

Re: Johnson V4 Powerpack question

Looks to me like it should be a 113-4028.
http://www.marineengine.com/newparts/part_search.php?part_num=584028&x=16&y=13
The fuel system may not be loosing prime, but are the high speed jets clean and not restricted?
Have you checked spark when it happens, are you actually dropping spark to some cylinders?

 

[daselbee]

Re: Johnson V4 Powerpack question

You may have a fuel pump that cannot keep up with the fuel demand at high speed. You might effectively be pulling the carb bowls almost dry.

When you slow down, fuel demand is not nearly as great, the bowls fill up again, and you take off, only to run the bowls almost dry again.
The "prime" of the system would not be affected.

As stated above, be sure to check spark on all cyls when the power loss is happening. Most common way is to rig a timing light, and look into it as the engine is running. No flash, intermittent flashes, etc are not good.