Force 70 cooling & starter issue

[john from md]

Re: Force 70 cooling & starter issue

I can't tell you what the box with the button is, we don't have anything like that on our engines. Maybe it is somekind of enrichment circuit?

The plugs are surface gap plugs, the same that are used for racing. These engines were designed for boats that were expected to be doing alot of skiing. When skiing and boarding, you are mostly at high power and these plugs are less prone to detonation than the L gap plugs. The down side to them is that the foul easily at lower speeds and must be cleaned more often. Also, you will never get as smooth an idle as you can with L gap plugs.
Don't ever substitute L gap plugs as you will burn a hole in a piston.

The water comes out of two places. Behind the motor leg, there are two exhaust relief ports. They allow the engine to start as water pressure is to great on start up for it to come out of the snout under water.

The main exhaust is either through the snout behind the prop and sometimes also through the vent holes in the propeller. The water comes out of the same place.

On the muffs, you should have most of the water coming out of the snout but still something should be coming out of the leg relief holes.

If you don't know when the water pump was changed, you should change it or risk burning up your engine the first time out.

John

 

[andybid]

Re: Force 70 cooling & starter issue

Clearly looking at the vid- I have no water throughput! (

I'll take it apart next week and have a check on it all.

I got the clymer shop book, It for 3.5 - 125hp Force from 1966 - 1985 I think. Not for 1992!! (Which I think my engine is)

Althogh it will give me lots of useful info, like what bits are called, I dont think it will serve me greatly for any disections! I think I will have to purchase a proper book. what would you reccomend?

I note your comment re the unidentified block with the button on. If all these engines were made in one place, why is it different to the US engines? Is there a difference between UK and US engines?
Mine is black, a lot I see on here are white, is this a uk thing?


Do you know any links to a 'change your water pump on a force 70' how to's? I think that would be useful to me.

Thanks john.
Andy

 

[john from md]

Re: Force 70 cooling & starter issue

The colors are just changes made for a different model year or the boat it was going on. As for the button thing, that could have been something specified by British import laws, who knows.

Clymer makes the same book for engines made from 1984 to 1999. I would send yours back and exchange it for the one you need.

Changing the water pump is easy and there may be a sticky at the top of the Force maintenance forum, but I'm not sure.

It goes like this.

Remove the cotter key from the shift rod in front of the leg.
Remove the bolts holding the snout on. Next, remove the hidden (usually allen) bolt in the snout area.
Remove the bolts on either side of the lower leg. (support the leg as it weighs about 50 pounds.

On top of the leg, is a box that the shaft goes through. It has four bolts on it. Remove the four bolts and lift off the box (water pump cover). Clean the shaft of any corrosion or contaminants and coat the shaft with light grease before doing this so you don't damage the Garlock seal on top of the cover.

The water pump is under the cover, note the way the vanes are bent. When you replace the impeller, you want to twist the cover as you are going down on the impeller in the direction that will result in the vanes being twisted as the old vanes were.

Don't forget to clean the stainless wear plate and to replace the gasket and woodruff key in the shaft.

Replace all bolts etc and you are finished.

NEVER run an engine without water even for a minute as the impeller will melt from friction.

John

 

[andybid]

Re: Force 70 cooling & starter issue

Right ho, Thank you.

I am off for a weekend break so will get to it next week. Thank you.