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  1. J

    Thermostat question -- 140 or 160 degrees?

    1998 Mercruiser 5.7 Alpha with Closed Cooling and Carburetor M048938 Thermostat question -- 140 or 160 degrees?
  2. J

    Anything I could do to prevent rusting of internal surfaces?

    Did another compression test today. Squirted 2 tbls spoons of engine oil into cylinder with low compression (only 30 psi). No improvement. Still only 30 psi. Did a type of leak down test using plastic bags. (My hearing isn't what it used to be, so needed a visual to help identify where air may...
  3. J

    What issues would a leaky riser cause?

    I did compression test again today after squirting 2 tbl spoons of engine oil into cylinder. No improvement. Did another type of leak down test. Brought bad cylinder (#5) to TDC. Loosened rockers to ensure valves weren't being compressed by rockers. Put plastic bags over carburetor, exhaust...
  4. J

    What issues would a leaky riser cause?

    I’m sorry. Is there a way to delete the other thread?
  5. J

    What issues would a leaky riser cause?

    Thanks for your response. I appreciate additional inputs and thoughts as I try to figure this out. Like you noted, it’s going to be harder to find once I tear it down, unless issue is obvious. I run in saltwater. Saltwater runs through the heat exchanger and out the manifolds. Coolant in the...
  6. J

    What issues would a leaky riser cause?

    I changed the exhaust manifolds and risers in May 2019.They may have been leaking before I changed them. I can’t remember if I found any water in the exhaust chamber. There was a lot of rust on the outside at the seam between the riser and manifold. Right now, oil is good. No steam in exhaust...
  7. J

    What issues would a leaky riser cause?

    What have others found as the reason for low compression following a leaky riser? What issues would a leaky riser cause? Valve problem? Ring problem? It depends? Thanks in advance for any additional info, 1998 5.7, with 2 bbl carb, FWC M048938
  8. J

    Anything I could do to prevent rusting of internal surfaces?

    Thanks. I'll do the following... hose the bores down with 30 wt oil or a smear of grease spray WD40 in the water jacket The plastic bags over the carb and exhaust pipe are for leak down test... to help identify where air is leaking. During the first leak down test, I could hear the air in...
  9. J

    Anything I could do to prevent rusting of internal surfaces?

    1998 Mercrusier 5.7L with 2 bbl carb. FWC. M048938 720 hrs Looking for advice. I am considering pulling the heads to have them refurbished during the offseason. (Reason why added below.) Boat will be outside under shrink wrap while heads are off. I read that it is NOT recommended to drain...
  10. J

    MerCruiser 5.7L Alpha -- Jackshaft Components -- replacing the bearings

    Question about replacing the bearings on a jackshaft. 1986 Rampage 24 Express with 58" jackshaft 1998 Mercrusier 5.7 M048938 Looking for instructions on 1) replacing the bearing marked #17 in the attached (the one on the side of the jackshaft closest to the engine) - Should it be pulled the...
  11. J

    Starter solenoid arcing

    1998 Evinrude 40 hp E40TLECR Outboard Motor Turned key and starter engaged for 2 seconds and then the Starter solenoid started arcing. When I remove the red power to the starter and turn key, solenoid clicks. I had removed starer to get to shift rod connector, to drop lower unit. To remove...
  12. J

    Confirming hose locations on tilt/trim motor

    Confirming hose locations on tilt/trim motor for install on new hoses. (I forgot to take a picture before removing old hoses.) The (low pressure) black hose (up) is on left? And the (high pressure) gray (down) is on right? I am all set with the hose locations on the manifold and rams.
  13. J

    Sporadic "chatter" near jackshaft / outdrive connection

    Hearing a "chatter" near jackshaft / outdrive connection. But it is not a constant noise. Noise only occurs sporadically. "Chatter" noise occurs while in neutral at idle (~650 RPMs). Upper unit is new. U-Joints recently greased. Gimbal bearing checked July 2019 while outdrive was off. It seemed...
  14. J

    Any way to protect zinc plated bolts in a marine environment?

    Is there a Rustoleum paint or other that will protect zinc plated bolts in a marine environment? I messed up and used zinc plated bolts to secure the swim platform. Only the bolt heads are exposed but they are already showing signs of rust. If there’s nothing that will protect them, I’ll have...
  15. J

    Question about port light repair (thickened epoxy in old screw holes?)

    Hi - I'm fixing a leaky port light. Have removed and will clean up surface before reinstalling. Before I reinstall, I am considering filling the existing screw holes with thickened epoxy and then drilling and tapping new holes before I screw the port light back in. My question - If I fill the...
  16. J

    Ignition timing lead

    Ignition timing lead 1998 5.7L V8 (M048938) 2 bbl Mercarb Thanks in advance for help on what some may find a silly question. New to Mercruiser engines and still learning. Appreciate all the great help on this forum. Where is the ignition timing lead typically found? Is the other end of...
  17. J

    Correct wiring for fuel pump?

    Hi all- I have gone through many posts looking for info about how to correctly wire the electric fuel pump (Mercury 861155A 3). Currently, the electric fuel pump is wired directly to the coil and turns on as soon as the key is turned to the ON position. I believe it should be wired to the...
  18. J

    Forward Gear Idle position vs Neutral?

    Tuning the idle for new carburetor. Starting with idle speed screw 2 turns in after just resting on the idle cam. Also, starting with idle mixture 1 1/4 turns out from seated. After reaching normal operating temperature, I’ll disconnect the throttle cable from the carb. The next step isn’t clear...
  19. J

    More curious about why. No overheat problems.

    1998 5.7L (M048938). FWC Alpha. 2bbl carb. Sea Water Pump. 1986 Rampage 24. I/O with jack shaft (engine is mid boat) I really enjoy reading the posts on this forum. There is a tremendous wealth of knowledge here! Reason for my post is that I am more curious about why. No overheat problems...
  20. J

    Part number for part pictured?

    Hello all- 1998 Mercrusier 5.7 (M048938) I am trying to identify the part number for the part pictured (see item circled in red). Under the protective sleeve is a metal hose between starboard exhaust manifold and intake manifold. Specifically, I am trying to find a replacement for the hose...
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