Force 120 - 1998 (Merc) - Temp alarm at idle

[buzzbomber]

Bought my first boat, has a 120 force on it.

Having issues with temp alarm at idle after about 2-3 minutes temp alarm sounds. If I put it in neutral and give it some gas temp alarm will go away pretty quickly or if I just throw it in gear and go faster temp alarm goes away quickly.

It alarmed twice at idle then for the rest of the day boat ran great but I avoided staying in idle for more than a minute.

I'm new to boating and trying to figure out the issue, since looking it up I should have killed the engine quickly. But I ran the boat for about 4-5 hours afterwords and it ran great so hope I didnt do any real damage.

From what I read it could be the impeller, the housing, or thermostat? does that sound right and Is there anything else I should replace or check?

Trying not to hose the engine, it runs great at speed and in reverse, just idle makes it heat up.

appreciate any advice.

 

[buzzbomber]

Re: Force 120 - 1998 (Merc) - Temp alarm at idle

Updated above post.

 

[pnwboat]

Re: Force 120 - 1998 (Merc) - Temp alarm at idle

Definitely take a look at the impeller. Look at the first entry at the top of this forum labeled "Sticky: Force & Chrysler FAQ and other great information". You'll see a listing for a step by step impeller change procedure.

 

[buzzbomber]

Re: Force 120 - 1998 (Merc) - Temp alarm at idle

Cool, thanks for the feed back. That guide should help a lot. Going to buy the water pump kit and a new thermostat and replace it this weekend. Hope that helps with the idle issues.

I'll post any results I get afterwords to hopefully help the next guy.

 

[buzzbomber]

Re: Force 120 - 1998 (Merc) - Temp alarm at idle

I'm looking for part numbers for the water pump repair kit, I found another posting but it listed a bunch of different numbers and the original poster never said which one was right.

18-3214 Kit #1
817275A2 Kit #2
47-43026T2 Impeller

F664068 Thermostat

Anyone know which if any of these will work?

 

[buzzbomber]

Re: Force 120 - 1998 (Merc) - Temp alarm at idle

Ok, just to help out any future 1998 120 force Engine Owners.

Issue: temp alarm at idle sounds after 2-3 minutes. Weak Telltale at idle. Strong at cruising speed no overheating.

Resolution: water pump kit.

I was skeptical just a water pump kit was going to resolve it as the impeller was just changed 3 months back by the last owner, After inspecting the impeller it did look new but it was a different size. I dont think the guy took the time to look up the right impeller.

If you need a pump kit for this motor order part# 18-3570

I've never worked on an Engine, didnt know what an impeller was until 2 weeks ago, so as far as replacing the pump kit it's pretty easy.

If you want to know how to do it watch this video:

http://www.youtube.com/watch?v=BiQNhFYFvdQ

The video is on a mercury but it's the same lower unit and just follow every step in the video and you'll be good to go. The Gear Shift rod is a little longer on the force but that's the only difference.

Tools you'll need:
- Metric Socket Set.
- Putty Scrapper & RTV silicon.
- Marine Grease. ( I used quick silver)
- Wire Brush.
- Gasket Sealant (Not required, but good).

All in all the kit + tools were around 100 bucks. Would have spent more having a shop do it and now I have a set of tools for the motor and learned a little somthin in the process.